Mix first 4 ingredients in a bowl until almost all the lumps are gone. Add the chocolate chips. Bake in a greased 9 X 13 pan at 180ºC or 25 minutes. Cool and cut into squares. Suggested box cake mixes ~ Pillsbury Plus Yellow, Butter or Devil's Food. I also used the Duncan Hines Fudge Marble mix. You take some of the batter and mix with the fudge packet. I needed to add a T or 2 of water just enough to mix. First spread and pat down in pan the plain yellow mixture then I added the fudge mixture and swirled it in pan. Came out great. * Also may want to try butterscotch chips, or nuts for variety. ----