01 -
Set your oven to 350°F. Prep an 8x8 inch glass dish by lining it with parchment and adding a light grease layer.
02 -
Whisk the butter with sugar, then mix in the melted chocolate and vanilla. Add eggs, blending lightly until just combined.
03 -
Use a sifter to mix cocoa, salt, flour, and baking powder into the wet mixture. Fold gently with a spatula until mixed.
04 -
Smooth the batter in the baking dish. Warm up the peanut butter for 15 seconds in the microwave, pour small spoonfuls on top, then create swirls with a knife.
05 -
Bake for 35-40 minutes, checking with a toothpick (it should come out with just a few moist crumbs). Let the dessert cool before cutting.