Preheat oven to 350°. Spray an 8x8” baking pan with non-stick spray and line with parchment paper, allowing some to hang over the sides to act as handles for lifting the brownies out at the end. If that makes ABSOLUTELY no sense to you, just really spray your pan really, really well. The brownies will come out. Pretty sure.
Melt butter in a small saucepan. Add chocolate and espresso to the melted butter and stir until melted and well mixed. Allow to cool.
While the chocolate is cooling, let’s make the peanut butter filling.
Place all the filling ingredients in a medium bowl and, using a hand mixer, beat everything together until mixed very well. It will have the texture of a shortbread cookie dough, and that’s exactly what you want. Now it’s time to press the dough into a 7.5” inch square. Here’s a good way to do that: Draw a 7.5” square on a piece of parchment paper with a pencil, then turn the paper upside down. (No graphite in our peanut butter, thank you.) You should still be able to see the square through the paper. Plop the peanut butter filling inside of the square, and place another piece of parchment on top of it. Peanut butter parchment sandwich. Using a rolling pin, gently press the peanut butter filling into the square shape. Finally, take your peanut butter parchment sandwich and place it on a small baking sheet or cutting board, then place it in the freezer to firm up while we finish up the brownies.
Sift flour, salt, baking powder, and cocoa powder together. Set aside.
Combine eggs and sugar in stand mixer and, using the whisk attachment, whip together for about 3-4 minutes, until the mixture thickens and lightens in color. Using really well whipped eggs like this helps to give the brownies their traditional “crackly paper” top. I love that part 😍
Drizzle the cooled chocolate mixture into the eggs and sugar and combine until completely incorporated. Remove the bowl from the mixer and, using a silicone or rubber spatula, fold the flour mixture in by hand just until the last bits of flour have completely mixed in. I don’t use a mixer for this part because over-mixing the flour can lead to too much gluten development. That’s just fancy baking talk for “it will make your brownies tough and chewy.” No thank you.
Place half of the batter in the prepared pan and, using a small offset spatula or your fingers, press it into all the corners and get it as flat as possible. Take your peanut butter filling out of the freezer and peel off the parchment paper. You should then be able to lay it precisely in the center of the pan, right on top of the batter.
Spread the remaining brownie batter evenly on top of the filling, making sure to get batter all along the edges, effectively “sealing in” your filling.
Sprinkle your chocolate and peanut butter chips evenly over the top give them a teensy push into the surface. Oh, I’m so excited for you!
Bake in a 350° oven for 30-35 minutes, turning the pan around half way through. I start checking at 25 minutes so I don’t over bake cuz no one wants a dry brownie.
How do you know when a brownie is done? Tricky question, since a toothpick inserted in the center will always come out with some chocolate on it, but this is my take. When they are done the edges of the brownies will be definitely set and the center will have no jiggle. You may also start to see some of the crackling of the top, usually near the edges as well. (They’ll finish their crackle as they cool and as you cut them.) Best bet? Take them out as soon as you see these signs since they’ll continue cooking in the pan for a few minutes.
Please, oh please, allow these to cool in the pan for at least 30 minutes to an hour. I know, I KNOW your instinct is to get these in your mouth at Olympic speeds, but you want to let that beautiful filling set a bit. You also want the brownies to cool down a little so you don’t have to do the dog pant when chewing. The wait will be worth it.
Okay, GO!