1 box yellow cake mix
1 stick melted butter
2 eggs
1 c. chocolate chips
1 can condensed milk
2 tbsp. butter

Mix cake mix, butter and eggs together. Press 2/3 into greased 9 x 13 inch pan. Melt chocolate chips, condensed milk, and butter (2 tablespoons). Pour over cake mixture in pan. Spread rest of "dough" on top of chocolate. Marble with spatula. Bake at 350 degrees for 25 minutes.