In a bowl, cream sugar and shortening. Add egg and vanilla; beat well. Combine dry ingredients and add alternately with milk to the creamed mixture. Spread in a greased 9-in. square baking pan. Bake at 350° for 20-25 minutes. Cool on wire rack. , Cut into nine servings. Split each serving horizontally and fill with whipped cream and strawberries. Replace top of cake; garnish with a dollop of whipped cream and more berries. Serve immediately.