A classic! My nana used to make it and thankfully I saved her recipe

Preheat your oven to 350°F (175°C) and grease a 9×13 inch baking dish.
In a large bowl, combine the chocolate cake mix, melted butter, and 1 egg. Mix until well combined. Press this mixture evenly into the bottom of the prepared baking dish.
In another large bowl, beat the cream cheese and peanut butter together until smooth. Add the remaining 2 eggs, one at a time, beating well after each addition.
Gradually mix in the powdered sugar and vanilla extract until smooth and creamy.
Fold in the chocolate chips.
Spread the peanut butter mixture evenly over the chocolate base in the baking dish.
Bake in the preheated oven for 35-40 minutes, or until the edges are set, and the center is slightly gooey.
Allow the cake to cool in the pan before cutting into squares and serving.
Variations & Tips

If you want to switch it up, try using a different flavor of cake mix—yellow or even a fun flavor like peanut butter. For a crunchy twist, throw in some crushed pretzels on top before baking. And if you have a nut allergy, you can substitute the peanut butter with a nut-free spread like sunflower seed butter. Enjoy experimenting with different variations and find your favorite!