American Flag Cake
American Flag Cake
Servings
24-32
This easy American Flag Cake is soft, moist, and comes together fast with a box mix base that tastes homemade. It’s topped with a simple mock Swiss meringue buttercream and fresh blueberries, raspberries, or strawberries for a festive finish. Perfect for 4th of July, Memorial Day, Labor Day, or any Patriotic celebration. We hope you have as much fun making it as we do!
Ingredients
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1 box yellow cake mix
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120 g (1 cup) all-purpose flour
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200 g (1 cup) granulated sugar
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½ tsp salt
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225 ml (¾ cup + 3 Tbsp) milk, room temperature (any kind of milk works)
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255 g (1 cup + 1 Tbsp) sour cream, room temperature
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113 g (1 stick) salted butter, melted and cooled
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3 whole eggs, room temperature (*see notes)
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1 tsp vanilla extract
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123 g (½ cup) pasteurized egg whites, room temperature (cannot be fresh egg whites)
- 450 g (3¾ cups) powdered sugar
- 2 tsp vanilla extract
- ⅛ tsp salt
- 452 g (4 sticks) salted butter, softened to room temperature (65-68°F)
- 275 g (½ pint) fresh blueberries
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340 g (1 pint) fresh raspberries or strawberries
Amplified Boxed Cake
Mock Swiss Meringue Buttercream
Toppings
Instructions
Amplified Boxed Cake
Preheat oven to 350ºF. Grease and flour a 9 x 13” pan, then line with parchment.
In the bowl of a stand mixer fitted with the paddle attachment (or using a hand mixer), add all ingredients and beat on medium speed for 2 minutes.
Pour the batter into the prepared pan.
Bake for 21-26 minutes until a toothpick comes out clean, rotating the pan halfway through and testing for doneness starting at 20 minutes.
Cool the cake in the pan for 15 minutes, then transfer to a wire rack to cool completely before frosting.
Mock Swiss Meringue Buttercream
In the bowl of a stand mixer fitted with the whisk attachment, add the egg whites and powdered sugar.
Start whipping on low speed, then increase to high for 1 minute.
While continuing to whip on high, add the salt, vanilla, and butter in chunks.
Once all the butter is added, let the mixer run for 7-10 minutes until the buttercream is light and airy.
Switch to the paddle attachment and mix on low for 8-10 minutes until extra smooth.
Assembly
If you’d like a flatter surface, trim some of the top, if needed.
Add a layer of buttercream to the top and sides of the cooled cake.
Press a wire rack to the top or use a knife to mark your flag square and stripes. Mark 10 rows for the red and white stripes.
Dot blueberries in even rows, filling the entire marked square.
Dot raspberries in the first two rows of the top, middle, and bottom of your marked lines.
Add buttercream to a piping bag with a size 2D closed star piping tip, then pipe slanted onto the remaining 4 rows, moving back and forth quickly to create a ruffle effect.
You can make this the night before, but we recommend adding the fruit on the day of serving to prevent them from getting too juicy.
Did you make this? We’d love to hear how it turned out! Leave a review
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Notes
- Serves: 24-32 slices and makes about 4 cups of buttercream.
- Storage: The assembled cake can be refrigerated for up to 2 days, just add the fruit right before serving. The unfrosted cake can be frozen for up to 2 months wrapped in plastic wrap and tin foil, then sealed in an airtight container.
- Leftover Buttercream: Store tightly covered at room temperature for 2 days, up to 2 weeks in the fridge, or up to 8 months in an airtight container or freezer-safe ziplock bag in the freezer (just dethaw overnight in the fridge).
- Cake Box Ingredients: Use only the ingredients listed in the recipe, not those on the box.
- Mixer: To mix the cake by hand, whisk by hand vigorously for 3-4 minutes. You can use a hand mixer for the buttercream, just skip the last step of mixing for 7-8 additional minutes.
- Cake Mix Brand: Our favorite is Duncan Hines!
- *White Cake: For a pure white color, use 1 box of white yellow cake mix and replace the whole eggs with 4 large egg whites (about 123 g or ½ cup), pasteurized or fresh, at room temperature.
- Egg Whites (Buttercream): Use pasteurized egg whites in the buttercream since they will not be treated with additional heat in this recipe.
- Buttercream Sweetness: This is a nice, light buttercream with minimal sweetness. For a sweeter buttercream, add an extra 30 g (¼ cup) of powdered sugar.
- Fruit: Feel free to use strawberries instead of raspberries for the red lines. Just cut them into ¼” slice and layer them across in the line.
- Piping Tip: We used a size 2D closed star piping tip, but you can use any large piping tip and technique you like for the buttercream lines.
Happy baking! ❤️
Emma & Eric
@birchberryco Happy 4th of July Birchberry fam!! 🇺🇸 For the full recipe, visit birchberryco.com (link in bio), click RECIPES at the top, and find American Flag Cake #4thofjuly #cake #americanflag #baking #bakingrecipe #baketok #aesthetic #asmr #cottagecore
♬ original sound - BringingTheNostalgia