Whisk cocoa powder with hot melted butter before adding other ingredients to bloom it, which intensifies chocolate flavor and eliminates any bitter undertones.

Dollop room-temperature peanut butter onto batter in a checkerboard pattern, then drag a toothpick through it for beautiful, even swirls without over-mixing.

Remove brownies when a toothpick inserted in the center still has a few moist crumbs attached (not clean); carryover cooking will set them to perfect fudgy consistency.

Toast the butter over medium heat until it turns golden with nutty aromatics, then cool slightly before using—this adds complex richness that elevates the entire brownie.

Allow brownies to cool in the pan for 30 minutes, then refrigerate for at least 2 hours before cutting with a hot, wet knife to achieve clean, professional-looking slices.