Go Back

American Flag Cake

American flag cake made as a patriotic sheet cake with a thick white buttercream layer and a clean blueberry canton, strawberry red stripes, and banana or frosting white stripes. This red white blue cake is assembled after baking and cooling so the fruit rows stay vivid and uniform.
Print Recipe Pin Recipe
Prep Time 45 minutes
Cook Time 35 minutes
cooling 1 hour
Total Time 2 hours 20 minutes
Servings: 20 servings
Course: Dessert
Cuisine: American
Calories: 360
Ingredients Equipment Method Notes

Ingredients
  

White cake
  • 1 box white cake mix Use 2 boxes total and follow the package directions for the required eggs, oil, and water.
  • 1 eggs Amount per box called for on the cake mix package (include total for 2 boxes).
  • 1 cup water Amount per box called for on the cake mix package (include total for 2 boxes).
  • 1 cup vegetable oil Amount per box called for on the cake mix package (include total for 2 boxes).
Frosting
  • 2 cup unsalted butter Softened.
  • 6 cup powdered sugar Also called confectioners’ sugar.
  • 2 tsp vanilla extract
  • 5 tbsp heavy cream Use 4–6 tbsp to reach spreadable consistency.
Decoration
  • 2 cup fresh blueberries
  • 2 lb fresh strawberries Hulled and sliced lengthwise.
  • 1 banana slices or extra white frosting Use banana slices for the white stripes, or use extra white frosting if preferred.

Equipment

  • 1 sheet pan

Method
 

Bake and cool the cake
  1. Heat your oven to the temperature on the white cake mix boxes, then bake the 2 cake mixes in a large 12x18 sheet pan (or two 9x13 pans joined together) following package directions until a toothpick in the center comes out clean.
  2. Cool the baked cake(s) completely before frosting so the buttercream spreads without melting.
Make the white buttercream
  1. Beat the softened unsalted butter until fluffy, then gradually add powdered sugar, vanilla extract, and 4–6 tablespoons heavy cream.
  2. Beat until smooth and spreadable, adding heavy cream as needed to get a thick layer that holds its shape.
Frost and decorate like a flag
  1. Spread a thick, even layer of white buttercream over the entire top surface of the cooled sheet cake.
  2. In the upper-left corner, arrange fresh blueberries into a dense rectangle to form the blueberry canton.
  3. Create red stripes by arranging rows of sliced lengthwise fresh strawberries flat across the length of the cake, keeping the spacing uniform.
  4. Fill the white stripes by piping extra white frosting in rows between the strawberry rows, or by placing thin banana slices for the clean white stripe look.
Chill and slice
  1. Refrigerate the decorated American flag cake until ready to serve, about 1 hour, so the fruit and frosting set.
  2. Slice into squares and serve chilled for the neatest rows and the most stable fruit topping.

Notes

Pro tip: keep your strawberry slices similar thickness and press them gently into the buttercream so the red rows look flat and even from edge to edge. Store the American flag cake covered in the refrigerator for up to 3 days; freezing is not recommended because the fruit topping can weep when thawed. For a lighter option, you can use a reduced-fat vanilla frosting substitute, but keep the layer thick to maintain stripe structure.