1. Prepare cake batter and bake in 8- x 8-inch baking pan sprayed with cooking spray according to package directions. Cool cake in pan 10 minutes. Remove cake from pan to wire rack; cool completely.
2. Combine sliced strawberries and sugar in large bowl; set aside.
3. Drizzle half of the chocolate syrup onto large serving plate. Cut cake layer horizontally in half; place bottom half of cake, cut-side up, on serving plate. Drizzle with 2 tablespoons caramel topping; top with half of the sliced strawberries and the remaining cake layer, cut-side down. Drizzle with remaining chocolate syrup and remaining 2 tablespoons caramel topping. Cover with remaining sliced strawberries. Top with Reddi-wip just before serving. Garnish with whole strawberries, if desired. Cut into 9 slices to serve.