Cream shortening; gradually add sugar, beating well at medium speed of an electric mixer. Combine flour, baking powder, and salt; add to creamed mixture alternately with milk, beginning and ending with flour mixture. Mix after each addition. Stir in vanilla. Beat egg whites until stiff peaks form. Gently fold into batter. Pour batter into 2 greased and floured 9-inch round cakepans. Bake at 350 degrees for 25 to 30 minutes or until a wooden pick inserted in center comes out clean. Cool in pans 10 minutes; remove from pans, and let cool completely on wire WHITE CUPCAKES: Spoon batter into paper-lined muffin pans, filling each cup two-thirds full. Bake at 350 degrees for 20 minutes. Remove from pans, and let cool on wire racks.