Heat oven to 350°F. Grease and flour 15x10x1-inch baking pan or 13x9-inch pan. In large bowl, combine all cake bar ingredients; stir until well blended. Pour into greased and floured pan.
Bake at 350°F. until toothpick inserted in center comes out clean. For 15x10x1-inch pan, bake 20 to 30 minutes; for 13x9-inch pan, bake 25 to 35 minutes.
In small saucepan, combine sugar, milk and margarine. Bring to a boil. Boil 1 minute, stirring constantly. Remove from heat; stir in chocolate chips until smooth. Pour and spread over warm bars. Cool 1 1/4 hours or until completely cooled. Cut into bars.