Black and Yellow Caramel Brownies

Heat oven to 350°F. Line 9x13 pan with parchment paper or lightly grease the pan.
Stir together chocolate cake mix, 1/3 cup evaporated milk, 10 tablespoons melted butter.
Reserve approximately 1/4 cup of the chocolate batter. Spread the rest in the pan and bake for 6 minutes. Remove from oven.
Scatter 1 cup semi-sweet chocolate chips onto hot chocolate batter.
Melt unwrapped caramels over low heat (stove top or microwave) with 1/3 cup evaporated milk until creamy. Pour caramel over chocolate chips.
Stir together yellow cake mix, 1 egg, and 1 stick very soft butter. Set half the yellow dough aside.
Using only half of the yellow dough, roll and flatten small portions in your hand. Lay flat pieces on the caramel layer.
Bake 6 minutes. Remove from oven.
In a medium saucepan or in the microwave, melt milk chocolate chips, 1 tablespoon butter, and sweetened condensed milk together until smooth. Pour over yellow cake layer.
To create the marbled top: flatten remaining yellow cake dough into pieces and lay onto milk chocolate. (It won't cover the whole pan.) Flatten remaining chocolate cake dough into pieces and sprinkle in places not covered by yellow dough.
Using a small spreader or knife, gently spread doughs but leaving messy, marbled bumps.
Bake 30 minutes or just until yellow parts start to turn golden. Remove from oven. Cool to room temperature. Store in airtight container.