Prepare, bake, and cool cake according to directions. Slice the top fourth off the cake; set aside. To make tunnel, use a sharp knife to carefully hollow out bottom of cake, leaving a 1/2-inch shell. Tear removed cake into 1-inch cubes.
In a large mixing bowl, beat cream cheese until fluffy. Beat in milk and lemon juice until smooth. Stir in extract and food coloring, if desired. Stir in cake cubes and strawberries. Fold in 1 cup whipped topping. Spoon into tunnel; replace cake top. Spread remaining whipped topping over top and sides of cake. Refrigerate four hours or overnight.
Yield: 12-16 servings.