01 -
Bake for about 30 minutes, just until the center is barely gooey. Let the pan hang out on the counter for half an hour. Then pop out the squares and let 'em chill another 30 minutes before you cut 'em up and dig in.
02 -
Scoop in half the brownie mix and even it out. Set the frozen peanut butter slab on top, then gently add the rest of the brownie batter, covering that peanut butter all the way.
03 -
Toss in your flour, cocoa powder, and salt. Use a rubber spatula to fold everything together until it just looks blended. Don’t overwork it.
04 -
Throw in the eggs, the extra yolk, and vanilla. Whisk for about a minute, until it comes together and gets a bit thick.
05 -
Pour in the sugar to your warm chocolate-butter mixture and whisk like crazy. Let this cool off until it feels only a little warm.
06 -
Grab a big bowl safe to microwave. Dump in the butter and chopped up chocolate. Nuke it in half-minute bursts, stirring each time, until it all melts and looks smooth.
07 -
Crank your oven to 350°F (175°C). Line your 8-inch square pan with fresh parchment paper, with enough hanging over the sides to make it easy to lift out.
08 -
Scoop peanut butter into a bowl that won't melt in the microwave. Heat it for about 20–30 seconds, just until it pours but isn't hot. Use parchment to line your 8-inch metal pan, making sure some sticks out the sides. Spread out the peanut butter in the pan and freeze for at least an hour until it's firm. Lift out the peanut butter slab using the parchment and stick it back in the freezer for now.