Chocolate and Peanut Butter might be one of the world's best combinations. I know for some 'foodie types' that chocolate and raspberry, or chocolate and orange might be more sophisticated combinations, but for me it doesn't get better than PB & chocolate.
Peanut Butter Brownies are an obvious no-brainer. You can start with a standard boxed brownie mix, or make homemade brownies (like my truffle brownies), either way the addition of a peanut butter swirl is crazy good.
I've mentioned before that Mike is a purist of sorts when it comes to desserts - he prefers classic chocolate chip cookies vs. anything with oatmeal, raisins or PB, simple chocolate cake with butter cream frosting, and plain, 'chewy' (as he'd say...) brownies. So, I added the peanut butter swirl to half of the pan. You can do this if you are unsure if you'll like it... but I'm telling you, you will!
Peanut Butter Brownies Recipe
Brownie Box Mix, prepared as directed (before it bakes)
Homemade Brownies (get my recipe here!)
6 tablespoons of chunky peanut butter
After pouring the batter into the prepared baking pan, dollop 6 tablespoons of peanut butter evenly over the brownie batter. With a knife, swirl the peanut butter into the chocolate batter, drawing your knife up and down the length of the pan. Bake as directed.
I always bake my brownies a few minutes short of instructed baking time to get a nice, gooey, "chewy" brownie.
Notice Mike's taken care of the plain side already. I love this Gold Touch Non-stick Baking Pan from William Sonoma ($26). It is my official 'brownie pan'.