American Flag Cake

American flag cake with a classic patriotic sheet cake layout—white frosting base topped with a blueberry canton, strawberry red stripes, and white frosting or banana stripes. This 4th of July cake uses two white cake mixes and a thick, spreadable buttercream for a clean, vivid flag design.

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Prep Time 45

Cook Time 35

cooling 1

Total Time 2 20

Servings: 20 servings

Course: Dessert

Cuisine: American

Ingredients Equipment Method Notes

Ingredients

White cake

2 box white cake mix Use the package directions for water, eggs, and any additional ingredients.

Buttercream frosting

2 cup unsalted butter Softened to room temperature.
6 cup powdered sugar
2 tsp vanilla extract
5 tbsp heavy cream Use 4–6 tbsp total until spreadable; add slowly.

Flag decoration

2 cup fresh blueberries Keep dry so the canton holds its shape.
2 lb fresh strawberries Hulled and sliced lengthwise for stripe rows.
1 banana slices Optional for the white stripes (or use extra white frosting).

Equipment

1 sheet pan

Method

Bake the sheet cake

Heat oven and bake both white cake mixes in a large 12x18 sheet pan (or two 9x13 pans joined together) according to package directions. Bake until a toothpick in the center comes out clean, then cool completely.

Make the white buttercream

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

Frost the cake

Spread a thick, even layer of buttercream over the entire top of the cooled sheet cake. Use an offset spatula or the back of a spoon to make the surface level for clean stripes.

Decorate the flag

In the upper left corner, arrange the fresh blueberries into a dense rectangle to form the canton. Press lightly so the berries sit flush without leaving gaps.

Create the red stripes

Arrange rows of sliced fresh strawberries flat across the length of the cake for the red stripes. Keep the rows uniform in thickness for a straight, even flag look.

Create the white stripes

Pipe extra white frosting in rows between the strawberry rows to form the white stripes, or place thin banana slices if using bananas. Continue until the full top pattern is complete.

Chill and slice

Refrigerate the cake until ready to serve. Slice into squares once chilled for cleaner cuts.

Notes

Pro tip: bake and cool the sheet cake fully before frosting—warm cake will make buttercream slide and blur the flag edges. Store covered in the refrigerator up to 4 days (freeze: no, fruit-topped cakes don’t freeze well). For a different dietary option, you can use a store-bought gluten-free white cake mix and follow its bake directions for a gluten-free patriotic sheet cake.