Combine sliced strawberries and 1 tablespoon sugar; let stand 20 minutes, stirring occasionally. Stir in melted strawberry spread. Cover and chill.
Combine 1/2 cup flour, 1 1/2 tablespoons sugar, baking powder, and salt in a bowl; cut in margarine with a pastry blender until mixture resembles coarse meal. Add milk, stirring just until dry ingredients are moistened.
Sprinkle remaining 2 teaspoons flour over work surface. Turn dough out onto floured surface, and knead 4 to 5 times. Divide dough; roll to 1/2-inch thickness. Cut into 2 hearts with a 3 1/4-inch heart-shaped cookie cutter (or into rounds with a 3-inch biscuit cutter). Sprinkle with remaining 1 teaspoon sugar. Place on a baking sheet coated with cooking spray. Bake at 400° for 10 minutes or until lightly browned.
Slice shortcakes in half horizontally; spoon strawberry mixture evenly over bottom halves. Place top halves of shortcakes on strawberry mixture. Top each with 1 tablespoon whipped topping. Garnish each with a fresh strawberry, if desired.