Slice a 1-inch layer off the top of the angel food cake.

Gently hollow out a trench in the cake, approximately 1 1/2 inches wide and 2 inches deep.

Tear the cake removed from the trench into small pieces.

In a separate bowl, combine skim milk and instant chocolate pudding mix.

Beat the milk and pudding mixture on low speed using an electric mixer for 2 minutes.

Gently fold the torn cake pieces and 1 3/4 cups of whipped topping into the pudding mixture.

Fill the hollowed-out trench in the cake with the prepared pudding and cake mixture.

Replace the top layer of the cake.

Spread the remaining whipped topping evenly over the sides and top of the cake.

Chill the assembled cake thoroughly before serving.