Combine margarine, water and chocolate squares in saucepan; bring to boil. Remove from heat. Stir in combined flour, sugar, baking soda and salt. Add eggs and sour cream; mix well. Pour into greased and floured 15x10x1-inch jelly roll pan. Combine cream cheese and sugar, mixing until well blended. Blend in egg. Spoon over chocolate batter. Cut through batter with knife several times for marble effect. Sprinkle with chocolate chips. Bake at 375°, 25 to 20 minutes or until wooden pick inserted in center comes out clean. Makes approximately 2 dozen.
Sour cream substitute: 2 2/3 tablespoons butter (soft) & 1/3 cup milk