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–+ servings

Flag Cake

A recipe for an easy-to-make cake with buttercream frosting that has a surprise flag when you cut into the cake.
5 from 7 votes
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Prep Time 1 hour
Cook Time 27 minutes
Total Time 4 hours 27 minutes
Course Dessert
Cuisine American
Servings 20
Calories 724 kcal

Equipment

  • (3) 9-inch cake pans
  • (1) 6-inch cake pan
  • (1) 4-inch round cookie cutter
  • parchment paper (cut out circles that will fit into the bottom of each pan)
  • sifter
  • 1 large star tip (1M)
  • 1 large piping bag
  • 3 baking strips (see note below)

Ingredients
  

Cake Ingredients
  • 1 ⅓ cups sour cream, room temperature
  • 1 ½ cups buttermilk, room temperature
  • 2 tablespoons vanilla extract
  • 8 egg whites, room temperature
  • ⅔ cup vegetable oil
  • 2 Duncan Hines white cake mixes
  • red food coloring
  • blue food coloring
Buttercream Frosting Ingredients
  • 2 ¼ cups (4 1/2 sticks) unsalted butter, room temperature
  • 1 ½ tablespoons vanilla extract
  • 2 teaspoons vanilla bean paste
  • 1 pinch of salt
  • ¼ cup plus 2 tablespoons heavy cream
  • 9-10 cups powdered sugar, sifted
  • shortening
  • extra powdered sugar (for coating the pans)

Instructions
 

Directions for Cake
  • Preheat oven to 325°F. Prepare (3) 9-inch cake pans and (1) 6-inch cake pan by coating with shortening and then dusting with powdered sugar. Cut out round parchment circles and fit them into the bottom of each prepared pan. Set pans aside.
  • In a large mixing bowl add the sour cream, buttermilk, vanilla, egg whites, and vegetable oil. Whisk until thoroughly mixed.
  • Sift the cake mix into the liquid mixture. Stir until combined and smooth, but don’t overmix.
  • Divide the cake batter between 3 medium bowls. In the third bowl, place a little more batter than the other two bowls so that there will be enough red batter for (1) 9-inch pan and the 6-inch pan. It does not take much batter for the 6-inch pan, so just eyeball it.
  • To the third bowl that has more batter, add several drops of red food coloring until you like the color. Fill the 9-inch and the 6-inch prepared pans with the red batter.
  • In another bowl of batter, add drops of blue food coloring and stir. Keep the color intensity the same as the red batter. Pour the blue batter into a prepared 9-inch pan.
  • Finally, pour the white batter into the last 9-inch prepared pan. To help ensure flat layers, place baking strips around the 9-inch pans. (See note below about baking strips and how you can make your own.) Bake layers at 325°F for 25-27 minutes or until a toothpick comes out clean. Cool on a wire rack.
Directions for Buttercream
  • Using a large mixing bowl and mixer, beat the butter until smooth. Add the vanilla extract, vanilla bean paste, salt, and cream. Beat well. Sift in the powdered sugar and beat until smooth, 3-5 minutes. Add more cream if needed for a thinner frosting.
Directions Cake Assembly
  • Level any domed layers with a knife by shaving off the peaks. Then use a long knife to split the white cake layer into two same-size round layers. Set aside one layer. Then use the 4-inch round cookie cutter to cut out a 4-inch round in the middle of the other layer. Discard the “donut” but save the 4-inch round.
  • Using the same long knife, split the 9-inch red layer into two same-sized round layers. Set layers aside for later. Then, using the cookie cutter, cut a 4-inch round out of the 6-inch cake layer. Discard the donut from the 6-inch layer, but save the 4-inch round.
  • Center the cookie cutter in the exact middle of the blue layer and cut a 4-inch round. Save the blue donut but discard the 4-inch round.
  • In the middle of a cake platter, place a small dollop of frosting to stabilize the bottom cake layer. Then place the layers in the following order with frosting spread between each layer: a red 9-inch layer, a white 9-inch layer, a red 9-inch layer, and the blue 9-inch donut. Inside the hole of the blue layer, place a white 4-inch round layer and frost it. Next, place the 4-inch red round layer into the hole. Finally, frost the whole cake with a thin layer of frosting. Then, using a large star tip, pipe buttercream stars all over the cake.

Notes

Parchment Paper

When using parchment circles in the bottom of your pans, make sure they lie flat. It is better to have a smaller paper so it doesn't go up the sides, which can distort the shape of the layer.

Baking Strips

To get a flat cake without a middle dome, use wet baking strips around the cake pan. You can buy these at craft stores in the cake-baking section, or you can make your own.
To create a baking strip using a towel, first cut a piece that is long enough to wrap around your cake pan and tall enough to fold over for a double layer. Dampen the strip so that it is very wet, but not dripping. Overlap the ends and secure them with safety pins until the strip fits snugly around the pan. Next, pour your batter into the pan and bake as usual, keeping in mind that it may take an additional 5 minutes or more because cakes typically bake more slowly with wet strips. The purpose of the baking strips is to prevent the edges of the cake from cooking too quickly, helping avoid a dome in the center.

Red Velvet

You can make the red layer into red velvet cake by adding 1 tablespoon of cocoa powder and 1 teaspoon of vinegar to the red batter.

Red Food Coloring

Some red food coloring turns brown.  I have found that Christmas Red Gel by Lorann Oils (click here for lorannoils.com) has a bright, non-changing red color.

Cutting the Layers

  • If you don't have a 4-inch cookie cutter, you can make a template from parchment paper and cut around it to make 4-inch cake layers. Also, a 4-inch round bowl can be used as a guide.  However, the more exactly you cut the layers, the better the cake will look.
  • Be sure to wipe off the cookie-cutter after you cut each layer so you don't transfer crumbs to the next layer.
  • The layers of this cake are easier to work with if you freeze them before frosting. If you make this cake over 2 days, freeze the layers overnight.  Otherwise, freeze layers for a couple of hours.

Homemade Piping Bag

If you don't have a piping bag, you can make one by using a gallon freezer bag. Cut off a bottom corner and place a star tip in that hole, and fill with frosting.

Yield

You can get 20 or more slices out of this cake.

Nutrition

Calories: 724kcalCarbohydrates: 98gProtein: 5gFat: 35gSaturated Fat: 18gPolyunsaturated Fat: 5gMonounsaturated Fat: 9gTrans Fat: 1gCholesterol: 72mgSodium: 409mgPotassium: 109mgFiber: 1gSugar: 77gVitamin A: 834IUVitamin C: 0.2mgCalcium: 159mgIron: 1mg
Keyword American Flag Cake, Buttercream Recipe, Buttermilk Cake Recipe, Cake Recipe, Flag Cake, Frosting Recipe, Homemade Flag Cake, How to Make a Flag Cake, Patriotic Cake Recipe, Red White and Blue Cake
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