Move oven rack to lowest position.
Sift cocoa over dry cake mix in large bowl. Stir to blend. Proceed with
mixing cake as directed on package. Bake and cool as directed for
10-inch tube pan. Carefully run knife along side of pan to loosen cake;
remove from pan. Using serrated knife, slice cake horizontally into four
layers.
Prepare whipped topping mix as directed on package, using 1 cup nonfat milk and 1 teaspoon vanilla. Fold in strawberry puree.
Place bottom cake layer on serving plate; spread with 1/4th of
strawberry topping. Set next cake layer on top; spread with 1/4th of
topping. Continue with other layers. Garnish with strawberries, if
desired. Refrigerate until ready to serve. Slice cake with sharp
serrated knife, cutting with gentle sawing motion.
Makes 16 servings