Ingredients
3 cups all-purpose flour
1/3 cup cornstarch
1 teaspoon baking soda
1 teaspoon salt
1 cup + 2 tablespoons unsalted butter, room temperature
3 cups granulated sugar
6 large eggs, room temperature
1 cup sour cream, room temperature
2 teaspoons pure vanilla extract
16 ounces cream cheese, room temperature
2 tablespoons unsalted butter, room temperature
4 cups powdered sugar
1 teaspoon vanilla extract
2 cups blueberries, washed
2 cups raspberries, washed
Instructions
Preheat oven to 350°F (175°C) and line a 13×18-inch baking sheet with parchment paper
In a bowl, whisk together flour, cornstarch, baking soda, and salt
In a mixer, beat butter and sugar until light and fluffy
Add eggs, one at a time, then mix in sour cream and vanilla
Alternately add dry ingredients and mix until incorporated
Pour batter into prepared pan and bake 25-30 minutes until golden
Let cake cool completely
For frosting: Beat cream cheese, butter, powdered sugar, and vanilla until smooth
Spread white frosting over cooled cake
Place blueberries in the top left corner in 7 rows for the blue field
Pipe white frosting stripes alternating with raspberry rows using parchment paper templates
Notes
Use parchment paper to create precise flag patterns before adding berries
Substitute frozen blueberries (thawed and drained) if fresh unavailable
Store covered at room temperature up to 24 hours or refrigerate for freshness
- Prep Time: 30
- Cook Time: 30
- Category: Desserts
- Method: Baking
- Cuisine: American
- Diet: Vegetarian
Nutrition
- Serving Size: 1 slice (1/16 of cake)
- Calories: 420
- Sugar: 60g
- Sodium: 500mg
- Fat: 25g
- Saturated Fat: 15g
- Carbohydrates: 58g
- Fiber: 3g
- Protein: 6g
- Cholesterol: 85mg