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Homemade Marshmallow Sauce for a S’more Ice Cream Sundae

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This delicious and easy marshmallow sauce brings my S’more Ice Cream Sundae all the way home.

Hi Bold Bakers!

The only thing more nostalgic than an ice cream sundae is an ice cream sundae that tastes like a S’more! This recipe for Homemade Marshmallow Sauce for a S’more Ice Cream Sundae is the perfect marriage of my two favorite summer time treats. Now you won’t need to be sitting around a campfire to be eating a S’more! Instead, get ready to dig into my rich chocolate and graham cracker ice cream — smothered in the fluffiest, most pour-able marshmallow sauce you’ve ever had.

What is Marshmallow Sauce?

You might be wondering how to make marshmallow sauce, but you’re probably also wondering what it is. Marshmallow sauce is, honestly, what I would describe as a magic sauce. It’s made of things that you might not expect and has a texture and flavor like anything you might have ever tried.

Similar to my marshmallow fluff, my Homemade Marshmallow Sauce is as light as air, extremely sticky, ooey and gooey just like a marshmallow when it melts. The difference between marshmallow fluff and sauce is that it is pour-able. This is what makes it ideal for completing my S’more Ice Cream Sundae. Its also perfect for pouring over all kinds of desserts, pies, fruits… There’s really nothing that cant be improved by Marshmallow Sauce!

[This delightful and delicious Marshmallow Sauce will even go great with many of my other homemade ice cream flavors! Go ahead and snag the recipe for your favorite here!]

What is the Soft Ball Stage?

The trick to making my Homemade Marshmallow sauce is making the beginning of homemade candy, but instead of turning this sweet syrup into candy it gets whipped to white fluffy perfection.

There are two parts to this sauce, and one part is just water with a tiny bit of gelatin. This is what allows the Marshmallow Sauce to hold onto its lightness. The other part of the sauce is a candy-like syrup or water, sugar corn syrup, and a bit of salt. The light corn syrup is what makes this sauce a sauce, thick and pour-able, while the sugar and dash of salt obviously give the sauce its sweet marshmallow flavor.

While the gelatin and water “bloom,” creating a jell-o like texture, the other ingredients simmer together to form a sweet and thick clear syrup. It’s super important to follow my exact instructions on how to treat this syrup, because candy making can be tricky. The secret to this is to leave the ingredients to simmer undisturbed until they reach exactly 240°F (480°C), which is what is called “soft ball stage” in candy making terms (many candy thermometers will have this stage marked). After you’ve reached this stage the rest is super simple, I just pour the hot syrup over the gelatin mixture and whip.

After 10-12 minutes, what you’ve got is on crazy tasty Homemade Marshmallow Sauce!

How to Make 2 Ingredient Ice Cream

My S’more Ice Cream Sunday starts with the ice cream. This ice cream represents the chocolate and graham cracker part of a S’more. It is rich, chocolatey, and loaded with crunchy graham chunks which means it’s both creamy and smooth while being full of texture.

Just like all of my other ice cream recipes, this one starts with a base of my famous 2 Ingredient Ice Cream. All you need to make the base is heavy whipping cream and sweetened condensed milk. After a quick whip up with a hand or stand mixer, the cream and condensed milk transform into the most lovely ice cream — the perfect blank canvas for any flavor of ice cream. To turn my 2 ingredient ice cream base into chocolate and graham ice cream, I simply add melted chocolate and crushed graham crackers.

Instantly, you’re halfway to a S’more ice cream sundae! All you need to do now is freeze the ice cream for a minimum of 6 hours or preferably overnight.

How to Make an Ice Cream Sundae

After I make my homemade chocolate and graham ice cream, and I whip up my magic Marshmallow Sauce, the only thing left to do is put the two together! To build this S’more Ice Cream Sundae I suggest going big and bold! This means 3 giant scoops of ice cream and a generous pour of marshmallow sauce. I can’t even describe to you how heavenly this sundae is. If you’ve never tried a S’more Ice Cream Sundae, then I’m telling you: today is the day!

S'more Ice Cream Sundae, Homemade Marshmallow Sauce

The Marshmallow Sauce recipe is from

4.43 from 21 votes
Marshmallow Sauce
Prep Time
30 mins
Cook Time
20 mins
Total Time
50 mins

This delicious and easy marshmallow sauce brings my S'more Ice Cream Sundae all the way home for that taste of your childhood.

Course: Dessert
Cuisine: American
Servings: 25 servings
Author: Gemma Stafford
Marshmallow Sauce
  • 1 cup ( 8floz/225ml) water divided
  • 1 teaspoon unflavored gelatin
  • 1 1/2 cups (12oz/340g) sugar
  • 1 cup (10oz/283g) light corn syrup ( there is no substitute for corn syrup)
  • 1/8 teaspoon salt
  • 1 teaspoon vanilla
Chocolate and Graham Cracker Ice Cream
  • 2 cups (16oz/450 ml) heavy whipping cream
  • 14 ounces (1 can/ 400ml) sweetened condensed milk, cold
  • 2/3 cup (4oz/115g) bittersweet chocolate , melted
  • 1 cup (3oz/85g) graham crackers, crushed
Marshmallow Sauce
  1. Place half of the water in the bowl of a stand mixer. Sprinkle over the teaspoon of unflavored gelatin, set aside.

  2. Put the remaining water, sugar, corn syrup, and salt in a small saucepan. Allow the sugar to dissolve over medium-low heat. You can gently swirl the pan to help the sugar dissolve but do not stir as this can cause the syrup to crack. Once the sugar has dissolved simmer undisturbed over medium heat until the syrup reaches soft ball stage or 240°F (480°C) when read on a candy thermometer. 

  3. Next, pour the hot mixture into the bowl with the bloomed gelatin mixture. Whip on a low speed for two minutes to cool down the mixture. Once cool and slightly frothy add vanilla, and whip on high speed for 10-12 minutes, until the mixture is thick, white, and fluffy. 

  4. Store Marshmallow Sauce in an airtight container in the fridge for 8 weeks. 

Chocolate and Graham Cracker Ice Cream
  1. Using a hand or stand mixer fitted with a whisk attachment whip the cold cream on medium/ high speed until soft peaks form.

  2. Turn off the machine and pour the condensed milk into the whipped cream.

  3. Turn the speed up to high and whisk until the mixture is thick and stiff peaks. Turn off the machine and stir in vanilla extract and the seeds scraped from 1 vanilla pod.

  4. Introduce a little of the ice cream base to the cooled melted chocolate to loosen it up. Then quickly introduce this to the base and mix through. Work fast or the chocolate will stiffen. Lastly, fold in crushed graham crackers.

  5. Transfer to an air-tight sealable container and freeze for a minimum of 6 hours or overnight before eating.

  6. Keep stored in the freezer for up to 6 weeks.

Recipe Notes

Marshmallow sauce: I keep mine in the fridge but you can keep it in the cupboard if you wish. Give it a good mix up before serving to soften it. 


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Katherine Cowgill by Teren Oddo Oct. 2015

Meet Gemma

Hi Bold Bakers! I’m Gemma Stafford, a professional chef originally from Ireland, and I’m passionate about sharing my years of experience to show you how to make game-changing baking recipes with over-the-top results! Join more than 1 Million other Bold Bakers in the community for new video recipes every week!

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Write a Comment and Review

  1. Christine Korthaus on February 21, 2019 at 10:31 am

    The ice cream recipe doesn’t have vanilla listed in the ingredients but it’s in the instructions. How much extract?

    • Gemma Stafford on February 21, 2019 at 12:23 pm

      Hi, thank you for letting me know. I would add 2 teaspoons. Enjoy!

  2. K on October 7, 2018 at 5:22 pm

    Can I use homemade corn syrup that’s made of white sugar?

    • Gemma Stafford on October 8, 2018 at 1:14 am

      Hi there,
      That is a simple syrup, and it will work in a marshmallow recipe. The issue for my recipe is getting it to the right stage, knowing that it is right.
      Corn syrup is a stable thing, always the same, and this is not true for home made simple syrup.
      I would need to give you specific instructions as I have not used this in my recipe I am reluctant to do so. Glucose can also be used, or golden syrup, both are invert sugars, and are stable too.
      Do a little research, get your simple syrup to the right consistency and all will be well, it is not a matter of just dissolving the sugar, you need to get it to firm ball stage (245F) and you need a sugar thermometer for this.
      I hope it helps, do a bit of reading,
      Gemma 🙂

  3. K on August 23, 2018 at 11:59 am

    I did see a recipe for homemade corn syrup. Will that work?
    How to Make Corn Syrup at Home – Homemade Substitute Recipe

    Cook time
    30 mins
    Total time
    30 mins

    Serves: About 2 cups

    ¾ cup drinking water
    2 cups granulated sugar
    ¼ teaspoon cream of tartar
    Pinch salt


    1. Add all ingredients in a large saucepan and stir to combine.
    2. Over medium-high heat, stirring constantly with a wooden spatula, bring it to a boil. Then let boil until it reaches 240 degrees F, 112 C. This is soft ball stage.
    3. Let cool on a cooling rack.

    Good to know:

    Soft-ball stage: 235-240 degrees F
    Firm-ball stage: 245-250 degrees F
    Hard-ball stage: 250-265 degrees F

    It can be stored in air-tight container for 2 months.

    • Gemma Stafford on August 24, 2018 at 8:38 am

      Yes, this is like a simple syrup/sugar syrup, commonly used for marshmallows, go for it!
      Gemma 🙂

  4. Carol Cripps on July 23, 2018 at 3:45 pm

    Although you’ve suggested this recipe for serving with ice cream, I bet it would be amazing, pureed warm over gingerbread cake fresh from the oven. I can’t wait to try it out.

    • Gemma Stafford on July 23, 2018 at 5:41 pm

      I bet it would!!! Good thinking.


  5. Manisha Weerasinghe on July 22, 2018 at 4:46 pm

    This is one of the recipes that I HATE. Because if one of the key ingredients are unavailable I won’t be able to make it. Here in Sri Lanka both corn syrup & glucose syrup are unavailable. I hate just looking into this picture of yummy goodness.
    Love your ice creams & all

    • Gemma Stafford on July 23, 2018 at 2:33 am

      Hi there Manisha.
      I know, that is indeed frustrating. However there is a way. you can make a sugar syrup/simple syrup for this purpose. I intend to post this, but you can google it. Cook it out for a few minutes until it becomes viscous. Dip a wooden spoon into the boiling sugar, allow to cool, it will be HOT, and touch it with your finger if cool enough, or the back of a metal spoon, it should feel sticky.
      I hope this will help, try it, then try the marshmallow fluff (
      Thank you for your comment, it is one that upsets others too!
      Gemma 🙂

  6. StuartofBlyth on July 20, 2018 at 7:54 am

    “… leave the ingredients to simmer undisturbed until they reach exactly 240°F (480°C) …”

    May I point out that 240°F is actually 115°C rather than the 480°C stated? More accurately it’s 115½°C so I suppose 115°C or 116°C would do.

    • Gemma Stafford on July 20, 2018 at 10:05 am

      Hi there Stuart,
      AHHHH! yes, you certainly may point this out, always open to correction when I get it wrong, in the heat of the moment as it were!
      I will go back to correct this right away.
      Thank you for kindly pointing this out,
      Gemma 🙂

  7. Yolanda Belinstein on July 20, 2018 at 5:41 am

    Hi Gemma. I love your receipts. Last year I discovered you on the internet and decided to make my own ice-creams, which are very tasty.
    About the marshmallow sauce: can I use glucose syrup instead of corn syrup? I can’t find corn syrup here in the supermarket, but I have glucose syrup. can it be a substitute?

    Thanks, Yolanda

    • Gemma Stafford on July 20, 2018 at 9:03 am

      Hi there,
      Corn syrup is an invert sugar, which means that it prevents sugar crystals from forming in things like candies and sauces.
      Glucose is also an invert sugar but the water content is lower.
      This can indeed be used as a substitute, but you may need to increase the liquids. I am not sure if this is true for this particular recipe, and it should only be about one extra tablespoon or so. I think I would try a straight swap, and judge it, you will know if you need more.
      Gemma 🙂

  8. Jill Pritchard on July 19, 2018 at 12:56 pm

    Hello Gemma, It’s been a while since talking to you so I figured I’d drop ya a line while I get the chance. Life of course is busy up north as usual as Kevin would know being from Tacoma area. I have been prepping my home to put it up on the market for sale while it’s hot, hot, hot! Although it is usually cooler than it has been this year, it is just so different than our homeland. I miss it so very much even after being in the US so long, I still check the weather every few days for my home of Kilkenny. It’s a lot cooler than even Washington if ya can imagine that! Quite a shocker, a! I don’t know how you can handle LA but I suppose you would have air conditioning which is a rare thing here.
    Anyway, sorry to keep ya so long but I was trying to think of what you were talking about with this “Dublin Mudslide”? I don’t recall it but I know if it is anything like the “Mudslide” Drink/Dessert that is served here in the US, you have a Winner! Well, that’s what my daughter says anyway and she’s had plenty from Applebee’s Restaurant so if you haven’t already tried it, maybe give it a go! Well I better tend to me Mum now, Alzheimer’s is such a terrible disease but I am thankful that she isn’t in much pain. I wish I could take her back home to see if she could recognize her old place. It is still there and her cousins are living there. I don’t think she has ever even met them but the homestead looks almost the same. Amazing how I can still remember the Biscuit Cupboard that’s still in the corner, oh, the memories!Take care and sorry for rambling again, As Always, Irish Jilli

    • Gemma Stafford on July 20, 2018 at 10:55 am

      Hi Jill,
      Thank you for this lovely post.
      Yes, the Irish, in common with many other peoples, never really leave their roots behind them. There is always that ‘pull’. I am lucky to be able to get back home a couple of times a year, and it recharges the batteries.
      It has been roasting in Ireland of late, temperatures up to 30c or so, and Kilkenny is always the hottest spot when these heatwave conditions happen, every 40 years or so!!!! Haha! we are used to this here in LA, and no AC in our little house, but we manage.
      I wish you could take your mum home too, but I know how difficult this would be. The journey would be really difficult for you, and that matters too. The past is a comfortable place for people with Alzheimers!
      Dublin mudslide needs a bump up on my list, thank you for reminding me about this. I agree with your daughter, it has been a popular request, and it is delicious.
      Thank you for being in touch Jill, always great to touch base,
      Gemma 🙂

  9. Marianna on July 19, 2018 at 12:18 pm

    Hello! 480C can’t be right! Soft ball should be around 120C.

    • Gemma Stafford on July 20, 2018 at 10:57 am

      Yes, Marianna, I was rightly corrected in an earlier post, wil lget that sorted asap.
      About 116c to be precise. sorry to confuse, we are on it,
      Gemma 🙂

  10. Chantese on July 19, 2018 at 11:37 am

    This recipe is very yummy! Makes my stomach growl

    • Gemma Stafford on July 20, 2018 at 11:34 am

      That is a call for you to make it! get going,
      Gemma 🙂

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