Heat oven to 375 degrees. Grease 2 cookie sheets. In a large bowl mix flour, granulated sugar, cocoa powder, baking powder and baking soda. Cut butter in pieces. With pastry blender or 2 knives cut butter into flour mixture until coarse crumbs form. with a fork stir in buttermilk or yogurt until mixture clumps together. Divide in half. Put each on a cookie sheet in a 6-inch round. Sprinkle each with sugar. Bake one at a time 20 minutes until pick inserted in center comes out clean. cool on sheet on rack 5 minutes before removing to rack to cool completely. To Make Strawberry Shortcake: Not more than 2 hours before serving. Layer with cream and berries. Top with cream. Garnish with a whole berry. Just before serving pour on chocolate topping.