Tackling this ambitious three-layer flag sheet cake is worth the impressive results for your 4th of July barbecue or picnic. This beautiful red, white and blue dessert makes a festive addition to any patriotic-themed celebration. The classic vanilla buttercream frosting pairs well with the natural sweetness and slight tartness of the berries. What better way to get your daily intake of antioxidants, right?

This cake is highly photogenic and will be the sweet highlight your friends and family will be talking about on social media after the long holiday weekend. You can make the vanilla cake ahead of time and when you’re ready to serve this dessert, whip up the vanilla buttercream and get ready for some fruit arrangement and cake frosting! Happy Independence Day!

Start your 4th of July BBQ with this Herbed Potato Salad recipe, paired with either this Maple-Mustard BBQ Chicken recipe or this Easy BBQ Baby Back Pork Ribs recipe.

Step up your game and consider these 12 Entertaining Tips for Elevating your 4th of July BBQ. If you are looking for some inspirations for a patriotic color theme, here are 15 Red White and Blue Recipes for the 4th of July. Need some suggestions on what dishes to serve this weekend? Browse our collection of All American 4th of July BBQ recipes. By Amanda Frederickson

  • Yields: 8 to 10 servings
  • Difficulty: Medium
  • Total: 55 mins 
  • Active: 15 mins 

Ingredients (18)

For the cake:

  • 3 cups all-purpose flour
  • 1 ½ teaspoons baking powder
  • 1 1/2 teaspoons baking soda
  • 1 1/2 teaspoons salt
  • 1 cup buttermilk
  • 1/3 cup vegetable oil
  • 2 teaspoons vanilla extract
  • 12 tablespoons unsalted butter, at room temperature
  • 1 ¾ cups granulated sugar
  • 3 eggs

For the vanilla buttercream:

  • 6 cups confectioners’ sugar
  • 12 tablespoons unsalted butter, at room temperature
  • 2 tablespoons milk, plus more, if needed
  • 2 teaspoons vanilla extract
  • 1/4 teaspoons salt
  • 4 pints of raspberries
  • 2 pints of blueberries


  1. Preheat oven to 350F. Line a 9” x 13” baking pan with parchment paper and spray with non-stick spray. In a large bowl, combine the flour, baking powder, baking soda and salt. Set aside. In a medium size bowl, whisk together the buttermilk, vegetable oil, and vanilla extract. Set aside.
  2. In the bowl of a stand mixer, cream together the butter and granulated sugar until light and fluffy, about 3 to 5 minutes. Add in eggs, one at a time. Reduce speed to low and alternate adding the flour mixture and buttermilk mixture in three additions, starting and ending with the flour mixture.
  3. Divide mixture among three cake pans and bake until a toothpick comes out clean, about 35 to 40 minutes. Transfer pans to wire rack to cool completely.
  4. When ready to assemble the cake, make the buttercream. In a bowl of a stand mixer fitted with a flat beater, combine the powdered sugar, butter, milk, vanilla extract, and salt. Beat on medium until light and fluffy. If frosting is dry, add 1 additional teaspoon of milk at a time to reach desired consistency.
  5. Decorate the flag cake by spreading a layer of buttercream over the top and sides of the cake. Transfer remaining buttercream to a piping bag fitted with a large star tip. In the upper left hand corner of the cake, add a rectangle of blueberries that is 7 rows across and 6 rows down. Starting at the bottom of the cake pipe out one line of frosting. Add two rows of raspberries parallel to the line of frosting. Repeat process 3 more times. Pipe out small stars on top of blueberries.