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–+ servings
American Flag Cake made with blueberries and raspberries
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American Flag Cake

This American Flag Cake has a moist vanilla sponge filed with fresh berries and topped with a light and creamy mascarpone whipped cream. 
Course Dessert
Cuisine American
Prep Time 20 minutes
Cook Time 40 minutes
Total Time 1 hour
Servings 14 people
Calories 594kcal
Author John Kanell

Ingredients

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 tsp baking powder heaping
  • 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

Instructions

For the Cake:

  • Preheat the oven to 350F. Prepare a 13" x 9" sheet cake pan by adding parchment paper.
  • Sift flour, baking powder, salt and granulated sugar. Give it a whisk and set aside.
  • Add egg whites, milk, vanilla, almond extract, and sour cream. Whisk together.
  • Attach a paddle attachment to the stand mixer. Add in room temperature butter and beat until creamy. 
  • On medium speed, beat for the dry into the butter until you get a crumby mixture. Add 1/2 of the wet mixture. Mix, then scrape the bowl down and add the remaining. Beat until combined. 
  • Cut the raspberries in half. Squeeze a little bit of lemon juice over the berries. Add some flour and toss until they're coated.  Gently fold the raspberries and blueberries into the batter by hand.
  • Pour the batter into the prepared sheet cake pan.
  • Throw in a few more berries. 
  • Bake for 35- 40 minutes and/or until a toothpick inserted comes out clean.
  • Let the cake cool to room temperature on a cooling rack.

For the Frosting:

  • In a stand mixer fitted with a whisk attachment, add heavy whipping cream and confectioners sugar.
  • Beat on high until whipped.
  • Add vanilla extract. Give it another whip on high.
  • Fold in mascarpone by hand using a spatula. Switch to a whisk and beat.

For the Assembly:

  • I trimmed the sides of the cake. You don't have to do this, but I wanted a nice fresh edge.
  • Use an ice cream scooper to add the frosting.
  • Smooth with an offset spatula.
  • Using a ruler, I sketched out my flag, then transferred the design to the buttercream.
  • If you’re making an American flag, add blueberries to the top left side of the cake. Add raspberries in lines. Repeat until the flag is finished. 

Video

Notes

This cake keeps really well in the fridge for a few days but as always I loved it most at its freshest, just after frosting it. If you do refrigerate the cake allow it to come to room temperature before eating for best results.
I used raspberries and blueberries for this cake but you can substitute any of your favorites in. Make sure to cut up larger berries and toss with some flour before folding into the batter.
This cake is LOADED with moisture so it will need to bake for a longer time. Everyone's oven is a bit different so keep an eye on the cake's center. I will use a skewer and the spring test to make sure the cake is not under-baked.

Nutrition

Serving: 1piece | Calories: 594kcal | Carbohydrates: 57g | Protein: 7g | Fat: 38g | Saturated Fat: 23g | Cholesterol: 116mg | Sodium: 230mg | Potassium: 230mg | Fiber: 4g | Sugar: 36g | Vitamin A: 1365IU | Vitamin C: 13.8mg | Calcium: 114mg | Iron: 0.6mg