Preheat the oven to 425°F (220℃) and line 2 baking sheets.

In a medium saucepan over medium heat, add the water, butter, and salt and heat until the mixture comes to a simmer, about 2 minutes.

Once simmering, add the flour all at once and stir vigourously using a wooden spoon. Cook until the dough clears the sides of the pan and forms a ball around your spoon as you stir, 2-3 minutes.

Remove from the heat and add a fourth of your whisked eggs, stir vigourously until combined (it will look like it is not coming together but keep stirring and it will). Repeat this process until all the eggs are added.The mixture should be smooth, shiny and loose but not runny.

Add the batter to a piping bag fitted with a large round nozzle*. Pipe 1 ½ inch (4 cm) wide round dollops onto your prepared baking tray leaving about 2 inches (5 cm) between each one.

Wet your finger and push down any peaks that are on the puffs so this doesn't burn while cooking. Sprinkle drops of water on the tray to create steam in the oven, this helps the puffs rise.

Bake for 15 minutes at 425℉ (220℃), then reduce the heat to 350°F (180℃) and continue cooking for 10-15 minutes until the cream puffs are golden brown and hollow-sounding when tapped. Do not open the oven while they're cooking. If the puffs are pale in color when pulled out of the oven they can sink and lose their shape.

Allow to cool completely on a cooling rack.

In a large heat-proof bowl add the chopped chocolate and set aside.

In a small saucepan on low heat add the heavy whipping cream and bring to a simmer. Turn the heat off and carefully pour the hot cream over the chocolate without stirring. Cover the bowl with cling-wrap and let the mixture sit for 3-5 minutes.

Gently whisk the chocolate into the cream until you have a smooth and glossy mixture. Set aside.

In a large bowl add the cold whipping cream and whip on medium-low speed using an electric mixer until stiff peaks form. Keep refrigerated until ready to use.

Using a serrated knife, cut the cooled puffs in half horizontally. Spoon a generous amount of whipped cream into the bottom of each puff and top with the lid. Drizzle with chocolate ganache and sprinkle generously with icing sugar. If needed, loosen the ganache by microwaving it for 30 seconds.

Serve immediately or refrigerate for up to 6 hours. You can also store the cream puffs in an airtight container in the freezer for up to a week.