4th of July Flag Cake (Easy American Flag Sheet Cake)
Fluffy vanilla sheet cake topped with creamy vanilla buttercream, then decorated with fresh blueberries and rows of strawberries to create a festive 4th of July American flag cake.
Equipment
- Measuring cups and spoons
- Mixing Bowls
- Sheet Pan
- Spatula
- Cooling rack
- Hand Mixer or Stand Mixer
Ingredients
Fluffy Vanilla Sheet Cake
- 2 ¼ cups all-purpose flour
- ¼ cup cornstarch
- 1 teaspoon baking powder
- ½ teaspoon baking soda
- ½ teaspoon salt
- ½ cup unsalted butter softened
- 1 ½ cups sugar
- ¼ cup neutral oil canola/vegetable
- 3 large eggs room temperature
- 2 teaspoons vanilla extract
- 1 tablespoon lemon juice
- 1 cup buttermilk room temperature
Vanilla Buttercream Frosting
- 1 cup unsalted butter softened (2 sticks)
- 2 ½ cups powdered sugar
- 2 teaspoon vanilla extract
- 1 –4 tablespoons heavy cream add as needed for texture
Flag Decoration
- Fresh blueberries about 2 cups
- Sliced strawberries about 3 cups
Instructions
Bake the cake
- Preheat oven to 350°F (175°C). Grease and line a 9x13-inch pan with parchment paper.
- In a bowl, whisk together flour, cornstarch, baking powder, baking soda, and salt.
- In a large bowl, beat butter and sugar for 2–3 minutes until light and fluffy.
- Mix in the oil.
- Add the eggs one at a time, beating well after each. Mix in vanilla and lemon juice.
- Add the dry ingredients in 3 additions, alternating with buttermilk (start and end with dry). Mix just until combined—don’t overmix.
- Pour batter into the pan and smooth the top.
- Bake 22–28 minutes, or until a toothpick inserted in the center comes out clean.
- Cool in the pan for 15 minutes, then cool completely before frosting.
Make the buttercream
- Beat the butter for 2 minutes until smooth and creamy.
- Add powdered sugar gradually, mixing on low at first, then increasing speed.
- Mix in vanilla.
- Add heavy cream 1 tablespoon at a time until the frosting is fluffy and easy to spread.
Decorate like an American flag
- Spread buttercream evenly over the cooled cake.
- Make a “blue square” in the top-left corner using blueberries.
- Add rows of sliced strawberries to create red stripes, leaving white frosting between them for the white stripes.
- Chill 20–30 minutes to set, then slice and serve.
Notes
- Measure flour correctly: Spoon and level the flour so the cake stays fluffy (too much flour can make it dense).
- Don’t overmix: Mix just until combined after adding the dry ingredients for a tender crumb.
- Cool completely before frosting: Warm cake will melt the buttercream and make it slide.
- Buttercream texture: Add heavy cream slowly—stop when it’s fluffy and spreadable (not runny).
- Decorate close to serving: Add berries within 1–2 hours of serving to prevent juices from bleeding into the frosting.
- Dry the fruit: Pat strawberries and blueberries dry before decorating so the top stays neat.
- Clean slices: Chill the cake 20–30 minutes, then cut with a sharp knife wiped clean between slice
