Equipment Needed
- 9×13 inch baking pan
- Mixing bowl
- Whisk or spatula
- Measuring cups
- Parchment paper or non-stick spray
- Cooling rack
Step-by-Step Instructions
First, I preheat my oven to 350°F (175°C) and prepare my 9×13 pan. I absolutely swear by lining it with parchment paper, leaving an overhang on the sides. After a mishap where I just greased the pan and the bars stuck stubbornly in the corners, I learned my lesson. The parchment paper guarantees a perfect, clean lift every single time. Then, in a large microwave-safe bowl, I melt my stick of butter. I let it cool for just a minute so it’s not scalding hot when I add the eggs.
To the warm, melted butter, I crack in the two large eggs. If I’m using it, I add the vanilla extract here too. I whisk this together by hand until it’s completely smooth and well combined. The mixture will look pale yellow and glossy. This is the only wet mixture you need to make. Next, I dump the entire box of dry yellow cake mix right into the bowl. At this point, it will look impossible—like too much dry mix for the wet ingredients. Trust the process.
I switch from a whisk to a sturdy spatula or wooden spoon and start to mix. It will be thick and seem crumbly at first, but as you keep folding and pressing, it will come together into a very stiff, oily dough. This is normal! It takes a bit of elbow grease, but I promise it will form a cohesive ball. Once the dry mix is fully incorporated, I fold in my chocolate chips. I use a full cup and a half because I love a chip in every bite. The dough will be very thick and heavy.(See the next page below to continue…)