Line a 9x9” baking pan with foil and spray with cooking spray. Preheat oven to 350 degrees.
Mix peanut butter, 1/2 cup granulated sugar, brown sugar, vanilla, and 1 egg in a large bowl with a spoon. The dough should come together easily. Press into the bottom of your prepared pan. (Spray your hands with cooking spray to avoid it sticking!)
Sprinkle chocolate chips over peanut butter layer.
Beat cream cheese, sour cream, 1 egg, and 1/4 cup granulated sugar in a medium bowl. Make sure all your ingredients are room temperature. Beat on high with a hand mixer, or use an electric mixer to get all the lumps out (or as many as possible). It’s easier if everything is soft to start with!
Pour cheesecake mixture on top of chocolate chips and spread to coat evenly. Sprinkle with Reese’s Pieces or other desired candy. Bake for 40-45 minutes, until the top just begins to brown. The center will still wiggle a little. Cool at least one hour at room temperature and then refrigerate until completely set, 4 hours or overnight. Slice into bars and serve.