This moist and festive Alton Brown American Flag Cake is layered with fresh berries, tender vanilla cake, and a rich mascarpone whipped cream frosting. Made with ingredients like cake flour, egg whites, sour cream, raspberries, and blueberries, it’s the ultimate patriotic dessert centerpiece. This recipe yields 14 slices and takes just about 1 hour from start to finish. It’s perfect for your 4th of July party, summer cookout, or any berry-filled celebration.

Alton Brown American Flag Cake Ingredients

For the Cake

2 1/4 cups cake flour (300g), plus a pinch for the berries
1 1/2 cups granulated sugar (342g)
1 heaping tsp baking powder
1 tsp kosher salt
1 cup whole milk (240ml), room temperature
1/4 cup sour cream (60ml), room temperature
1 tbsp vanilla extract
6 egg whites, room temperature
3/4 cup unsalted butter (176g), room temperature
1 tbsp lemon juice
18 oz raspberries
18 oz blueberries

For the Frosting

3 cups heavy whipping cream (720ml), cold
1 cup confectioners’ sugar (125g)
8 oz mascarpone cheese (225g), room temperature
1 tsp vanilla extract

How To Make Alton Brown American Flag Cake

Preheat oven and prep pan: Set oven to 350°F and line a 13×9-inch sheet cake pan with parchment.
Mix dry ingredients: Sift flour, sugar, baking powder, and salt into a bowl.
Mix wet ingredients: Whisk together milk, sour cream, egg whites, and vanilla.
Cream the butter: Beat butter in a stand mixer with paddle attachment until creamy.
Combine ingredients: Add dry mix to the butter and beat to a crumb. Gradually add wet mix in two parts, mixing and scraping bowl between additions.
Prep berries: Halve raspberries, sprinkle with lemon juice and flour. Gently fold in both berries.
Bake: Pour batter into pan and scatter a few extra berries on top. Bake for 35–40 minutes or until a toothpick comes out clean. Let cake cool fully.

For the Frosting

Whip cream: Beat heavy cream with confectioners’ sugar until fluffy.
Add vanilla: Mix in vanilla extract.
Incorporate mascarpone: Fold mascarpone in by hand, then whisk until fully smooth.

Assembly

Trim and frost: Optionally trim cake edges. Use an ice cream scoop to place frosting, then smooth it with an offset spatula.
Decorate: Sketch a flag design with a ruler. Add blueberries to the top-left and line up raspberries to mimic stripes. Use any berry pattern you like.

Recipe Tips

Toss berries with flour: This helps prevent sinking in the batter.
Use room temp ingredients: Ensures smooth blending and even baking.
Cool completely before frosting: Prevents melting and sliding.
Chill for storage: Store frosted cake in the fridge for up to 3 days.
Adapt the design: Use your favorite fruit combo or a free-form berry design.

How To Serve American Flag Cake

This festive cake is perfect served chilled or at room temperature. Pair it with iced tea, lemonade, or a celebratory cocktail like a berry spritzer. It’s a show-stopping dessert that’s just as great at barbecues as it is for July 4th brunch.

How To Store American Flag Cake

Refrigerate: Keep covered in the fridge for up to 3 days.
Freeze (Unfrosted): You can freeze the plain cake for up to 1 month. Thaw and frost fresh before serving.

American Flag Cake Nutrition Facts (per slice)

Calories: 594
Total Fat: 38g
Saturated Fat: 23g
Carbohydrates: 57g
Sugar: 36g
Protein: 7g
Sodium: 230mg
Fiber: 4g

FAQs

Can I use frozen berries?
Fresh is best for decorating, but frozen berries can be folded into the batter if thawed and drained.

Can I make this cake ahead of time?
Yes! Bake the cake a day ahead and frost just before serving for best freshness.

What’s a good mascarpone substitute?
Full-fat cream cheese can work, but the texture will be thicker.

Why use egg whites instead of whole eggs?
Egg whites give the cake a lighter texture and whiter crumb—perfect for showcasing the berry colors.

Do I have to make the flag design?
Not at all! Scatter berries for a rustic look or arrange them however you like.

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Alton Brown American Flag Cake