American Flag Cake

American flag cake made as a patriotic sheet cake: two baked white cake layers frosted in thick buttercream and topped with a crisp blueberry canton, uniform strawberry red stripes, and white frosting (or banana) stripes. This 4th of July cake slices into clean squares for easy serving.

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Prep Time 45

Cook Time 35

Cooling 1

Total Time 2 20

Servings: 20 servings

Course: Dessert

Cuisine: American

Calories: 420

Ingredients Equipment Method Notes

Ingredients

White cake

2 box white cake mix Use the ingredients listed on the box (eggs, water, oil/butter) for both boxes.

Frosting

2 cup unsalted butter Softened.
6 cup powdered sugar
2 tsp vanilla extract
5 tbsp heavy cream Use 4–6 tbsp as needed for a spreadable texture.

Decoration

2 cup fresh blueberries Rinse and dry for easier placement.
2 lb fresh strawberries Hulled and sliced lengthwise.
1 banana slices Optional: use for white stripes, or use extra white frosting instead.

Equipment

1 sheet pan

Method

Bake the sheet cake

Bake both white cake mixes in a large 12x18 sheet pan (or two 9x13 pans joined together) following package directions, until a toothpick comes out clean. Let the cakes cool completely before frosting.

Make the white buttercream

Beat softened unsalted butter until fluffy, about 2 minutes. Gradually add powdered sugar, then mix in vanilla extract and heavy cream until smooth and spreadable.

Frost and design the flag

Frost the entire top of the cooled sheet cake with a thick, even layer of white buttercream. Use a spatula to keep the surface level for clean stripe lines.
In the upper left corner, arrange fresh blueberries into a dense rectangle to form the canton. Press them lightly so the shape stays crisp.
Create the red stripes by arranging rows of sliced fresh strawberries flat across the length of the cake. Keep the rows uniform in height and spacing.
Fill the white stripes by piping extra frosting in rows between the strawberry rows, or by placing thin banana slices. Make sure the white lines run straight from side to side.

Chill and slice

Refrigerate the cake until ready to serve. Slice into squares just before serving for best structure.

Notes

Pro tip: cool the cake fully before frosting so the buttercream sets without sliding, and dry berries well so they don’t weep on the stripes. Store in the refrigerator up to 3 days; freezing is not recommended because fresh fruit texture degrades. For a lighter option, swap 1 cup of powdered sugar for an equal amount of reduced-fat powdered sugar to cut richness while keeping the piping style.