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4.45 from 58 votes
Giant muffins are moist and tender, loaded with beautiful floral flavor from vanilla and sweet blueberries, and elevated with refreshing lemon zest.
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Jumbo Lemon Blueberry Costco Muffins Recipe
Prep Time
15 mins
Cook Time
40 mins
 

Enjoy big soft Costco muffins with golden crispy domes bursting with floral blueberries and fresh lemons, easily made from scratch at home.

Servings: 6 muffins
Author: Gemma Stafford
Ingredients
  • 2 ⅔ cups (13 ⅓ oz/378 g) all-purpose flour
  • 1 cup (8 oz/225 g) granulated sugar
  • 1 tablespoon baking powder
  • ½ teaspoon salt
  • ¼ teaspoon baking soda
  • 2 large eggs, at room temperature
  • 1 cup (8 fl oz/240 ml) buttermilk
  • ⅓ cup (2½ fl oz/71 ml) vegetable oil
  • ⅓ cup (2 ½ oz/71 g) plain yogurt
  • 5 tablespoons (2 ½ oz/71 g) butter, melted
  • 1 tablespoon lemon zest
  • 1 teaspoon pure vanilla extract
  • 1 ½ cups (7 ½ oz/213 g) blueberries (fresh or frozen)
Instructions
  1. Preheat the oven to 375°F (190°C) and generously butter a 6-cup jumbo muffin tin. Set aside.
  2. In a large mixing bowl, combine the flour, sugar, baking powder, salt and baking soda.
  3. In a separate large mixing bowl, whisk together the eggs, buttermilk, oil, yogurt, butter, lemon zest and vanilla until smooth.
  4. Combine the wet and dry ingredients until it just comes together (don’t overmix), then gently fold in the blueberries.
  5. Divide the batter evenly among the muffin cups (the batter will reach to top or come close – this is fine).
  6. Bake on a middle rack in the oven for 35-40 minutes, until golden on top and a skewer inserted into the center comes out clean.
  7. Let cool in the pan for 15 minutes before removing – serving warm or at room temperature.
  8. These are best eaten the day they are made but you can store completely cooled leftovers in an airtight container at room temperature for up to 2 days.