Flag Cake

Ingredients

• 2 sticks unsalted butter 1 cup, 1/2 pound or 225 grams, softened
• 2 cups sugar
• 4 large eggs at room temperature
• 2 teaspoons pure vanilla extract
• 4 cups cake flour
• 1/3 cup cornstarch
• 2 teaspoons baking powder
• 1 teaspoon baking soda
• 1 teaspoon table salt
• 2 cups buttermilk 475 ml, well-shaken
• 8 ounces cream cheese block, at room temperature
• 1/2 cup butter 1 stick or 1/4 pound, at room temperature
• 1 teaspoon vanilla extract
• 3 cups powdered sugar
• powdered sugar
• 1 cup blueberries 1/2 pint, about 170 grams, very dry
• 3 cups raspberries 1 1/2 pints, about 360 grams, very dry