Grease and flour a 9x13 pan. In a large pan, melt the margarine and chocolate. Add remaining ingredients and mix well. Spread in the pan.
*** Filling ***
3.
In a small bowl combine the cream cheese with remaining ingredients except for the chips. Blend until smooth and fluffy. Spread over chocolate mixture and sprinkle with chips. Bake 25-35 minutes and test with a toothpick. Remove, sprinkle with marshmellows and bake 2 minutes more.
*** Frosting ***
4.
In a small pan, melt the margarine, chocolate and milk. Beat in cream cheese and powdered sugar with an electric mixer until smooth. Immediately pour over marshmellow layer and swirl together.