The most delicious and dazzling American Flag Cake — making it the best Fourth of July celebration cake! You get a giant, fluffy and moist vanilla sheet cake topped with a decadent, sweet cream cheese frosting, and it’s finished with vibrant fresh berries in a simple design that mimics the American flag.
This easy flag cake is a recipe tradition you’ll want on repeat every year — and it doesn’t just have to be for the Fourth of July.
You can make this flag cake for a birthday and simply scatter fresh berries all over the top, or come up with your own captivating design out of fresh fruit. You can also make it featuring a different country — just try to find fresh fruit that highlights that country’s flag colors, or tint your frosting and pipe it to match the design, omitting the fruit.
This extra-large cake is baked in a cookie sheet pan making enough to feed a crowd, so it’s ideal for lots of company and various celebrations. It’s like the vanilla version of a chocolate Texas sheet cake — in other words, it’s dangerously delicious!
Flag Cake Ingredients (Cake Base)
- All-purpose flour: The main ingredient for the structure of the cake. Use regular all-purpose flour — unbleached or bleached both work fine.
- Cornstarch: Using this in addition to the flour allows for more liquid to be added to the batter, helps build structure, and yields a fluffier cake.
- Baking powder and baking soda: These two leavening agents make the cake puff up as it bakes. Check the dates on both to ensure they aren’t expired.
- Salt: Brings out all the flavors of the cake and balances its sweetness.
- Granulated sugar: Sweetens the cake and tenderizes the crumb.
- Unsalted butter: Only use unsalted butter here or the cake will be overly salty.
- Avocado oil: Vegetable oil or light olive oil can be substituted.
- Eggs: Bring eggs to room temperature before beginning so they blend smoothly into the batter and the cake rises better.
- Vanilla extract: Real vanilla extract is recommended if possible.
- Buttermilk: For best results use real buttermilk, not a homemade substitute of milk and vinegar.
Flag Cake Topping Ingredients
- Unsalted butter: Use unsalted butter or the frosting will come out too salty. Bring to room temperature so it whips up smooth and fluffy.
- Cream cheese: A good quality cream cheese such as Philadelphia is recommended. It doesn’t need to be fully at room temperature — 20 to 30 minutes out of the fridge is sufficient.
- Vanilla extract: Adds a boost of flavor to the frosting.
- Powdered sugar: A super-fine sugar that is essential for a smooth, non-gritty cream cheese frosting.
- Fresh berries: You’ll need strawberries, blueberries, and raspberries to create the flag design pictured. All strawberries can be used in place of strawberries and raspberries if preferred — you’ll need about 1.5 lbs total.
How to Make a Flag Cake Step by Step
Prepare oven and pan: Preheat oven to 350°F. Spray a rimmed 18 x 13 x 1-inch baking sheet with non-stick cooking spray, then lightly dust with flour and shake out the excess. Set aside.
Whisk dry ingredients: In a large bowl, whisk together the flour, cornstarch, baking powder, baking soda, and salt until well combined.
Cream butter and sugar: In the bowl of a stand mixer fitted with a paddle attachment, beat the butter and sugar together on medium-high speed until light and fluffy, about 3 to 4 minutes. Add the oil and continue to mix until combined.
Add eggs and vanilla: Add the eggs one at a time, mixing well after each addition, then blend in the vanilla extract.
Alternate dry ingredients and buttermilk: With the mixer on low speed, add the flour mixture in three additions, alternating with the buttermilk in two additions, beginning and ending with the flour mixture. Mix just until combined — do not overmix.
Bake: Pour the batter into the prepared pan and spread it into an even layer. Bake for 20 to 25 minutes, or until a toothpick inserted into the center comes out clean. Allow the cake to cool completely in the pan before frosting.
Make the frosting: Beat the butter in a stand mixer on medium-high speed until fluffy, about 2 minutes. Add the cream cheese and mix until smooth and well combined. Blend in the vanilla extract, then gradually add the powdered sugar on low speed until fully incorporated. Increase speed and beat until light and fluffy.
Frost and decorate: Spread the cream cheese frosting in an even layer over the cooled cake. Arrange the blueberries in the upper-left corner to form the star field, then create alternating horizontal stripes across the rest of the cake using sliced strawberries and raspberries to represent the red stripes, leaving the frosting exposed for the white stripes.
Refrigerate until ready to serve. This cake is best enjoyed the day it is decorated, as the fresh berries are at their most vibrant and the frosting stays firm and fresh.
