In a medium bowl, stir together the berries and 3 to 4 tablespoons sugar; set aside.
In a small bowl, combine flour, cornmeal, 1/4 sugar, baking powder, salt, and baking soda. Cut in butter until mixture resembles coarse crumbs. Add buttermilk and milk to flour mixture. Stir just to moisten. Place 6 3-inch baking ring molds on an ungreased baking sheet. Lightly coat ring molds with cooking spray. Spoon dough into ring molds. (Or, omit ring molds. Drop dough into 12 mounds on a large ungreased baking sheet.)
Bake in a 350 degree F oven about 25 minutes for rings, or 12 to 15 minutes if using dropped dough, or until a wooden toothpick inserted near the center comes out clean. Cool in ring molds for 5 minutes. Remove from molds. Cool on a wire rack about 10 minutes. Or, remove dropped shortcakes to a wire rack to cool slightly.
To serve, cut ring shortcakes in half horizontally, or if using dropped dough, use 2 mounds for each serving. Spoon half of berries and whipped cream over bottom layers. Replace top layers. Top with remaining berries and whipped cream. Makes 6 servings.