Preheat oven to 350 degrees. Grease a 13x9-inch aluminum foil-baking pan. In order to create two layers you will need to divide ingredients into separate batters. Microwave together the chocolate and butter on high setting for 2 minutes. Stir in 2 cups of the sugar and blend well. Stir in 4 eggs and 1 cup of flour. Spread this mixture in the greased pan. Beat cream cheese, gradually adding remaining ingredients. Combine well and spoon second mixture over batter already in pan; then swirl together lightly stirring with knife to create a marble-like pattern. Bake in preheated oven at 350 degree for 40 minutes or until toothpick has grainy fudge bits but is not clean, like in a cake.