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Copycat Costco Sheet Cake: Perfectly Fluffy & Easy

Copycat Costco Sheet Cake
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Make your own Costco-style sheet cake at home! This recipe delivers a fluffy vanilla cake with a creamy mousse filling, perfect for any celebration.

Ingredients

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  • 3 cups all-purpose flour
  • 1 ½ cups granulated sugar
  • 1 tablespoon baking powder
  • ½ teaspoon salt
  • 1 ½ cups milk
  • ¾ cup unsalted butter, softened
  • 3 large eggs
  • 1 ½ teaspoons vanilla extract
  • ½ cup sour cream
  • For the Mousse Filling:
  • 1 cup heavy cream
  • ½ cup powdered sugar
  • 1 teaspoon vanilla extract
  • For the Frosting:
  • 1 ½ cups unsalted butter, softened
  • 3 ½ cups powdered sugar
  • ½ cup milk
  • 1 ½ teaspoons vanilla extract
  • ½ teaspoon almond extract (optional)

Instructions

  1. Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking pan.
  2. In a large bowl, whisk together the flour, sugar, baking powder, and salt.
  3. Add the milk, softened butter, eggs, vanilla extract, and sour cream to the dry ingredients.
  4. Beat with an electric mixer on medium speed until well combined and smooth, about 2-3 minutes.
  5. Pour the batter into the prepared baking pan.
  6. Bake for 30-35 minutes, or until a wooden skewer inserted into the center comes out clean.
  7. Let the cake cool in the pan for 10 minutes before inverting it onto a wire rack to cool completely.
  8. While the cake cools, prepare the mousse filling. In a chilled bowl, whip the heavy cream, powdered sugar, and vanilla extract until stiff peaks form.
  9. Once the cake is completely cool, carefully slice it horizontally into two layers.
  10. Spread the mousse filling evenly over the bottom cake layer.
  11. Place the top cake layer over the mousse.
  12. Prepare the frosting. In a large bowl, cream together the softened butter and powdered sugar until smooth.
  13. Gradually add the milk, vanilla extract, and almond extract (if using), beating until light and fluffy.
  14. Frost the top and sides of the cake.

Notes

  • For an extra moist cake, you can brush the cake layers with a simple syrup before adding the filling.
  • Ensure all ingredients for the frosting and filling are at room temperature for the best texture.
  • Decorate with sprinkles or colored frosting to match your celebration theme.

Nutrition

Find it online: https://savoryskies.com/copycat-costco-sheet-cake/