1 cup butter, softened
1 1/2 cups sugar
2 large eggs
1 cup buttermilk
1 teaspoon vanilla extract
1 (1-ounce) bottle red food coloring
1 teaspoon vinegar
2 1/2 cups cake flour or all-purpose flour
1 tablespoon cocoa powder
1/4 teaspoon salt
1 teaspoon baking soda
3 cups heavy whipping cream
1 cup powdered sugar
3 pints fresh strawberries, halved
2 cups fresh blueberries
1. Preheat oven to 350°. Beat butter and sugar together in a large bowl; beat in eggs. Stir in buttermilk and next 3 ingredients.
2. Combine flour and next 3 ingredients in a medium bowl. Add flour mixture to butter mixture, stirring until well blended. Pour batter into 2 greased and floured 8-inch round cake pans.
3. Bake 30 minutes or until a wooden pick inserted in center comes out clean. Remove from pans, and cool completely on a wire rack. Cut each cake layer in half horizontally to make 4 layers.
4. Beat whipping cream and powdered sugar until soft peaks form. Spread one-fourth whipped cream mixture over 1 cake layer; top evenly with one-fourth berries. Repeat with remaining cake layers, whipping cream mixture, and berries.