Try this Peanut Butter Gooey Bars recipe
Using a boxed yellow cake mix as a structural base for bar cookies originated in mid-century convenience cooking, substituting pre-blended flour and leavening agents for measured dry goods. Mixing the dry cake powder directly with fat, peanut butter, and eggs creates a stiff dough rather than a pourable batter, which requires pressing rather than pouring into the pan. Achieving the correct density relies on beating the initial four components at medium speed for precisely two minutes to incorporate enough air for structural integrity. When adapting this formula for dietary restrictions, gluten-free commercial flour blends can replace the wheat-based cake mix, though adding one extra quarter teaspoon of xanthan gum is necessary to prevent crumbly squares. Dairy-free variations require substituting plant-based margarine for melted butter and using coconut-based condensed milk, though these alternatives alter the moisture retention during the final thirty-minute bake at 350 degrees Fahrenheit. Dividing the dough requires allocating half the mass for the bottom crust, which pre-bakes for ten minutes before receiving the chocolate chips and sweetened condensed milk layer. Letting the pan cool completely on a wire rack allows the condensed milk and semi-sweet chocolate matrix to set fully, yielding clean cuts when sectioned into sixteen equal portions.