- 1 stick butter
- 9 ounces bittersweet chocolate
- 2 eggs
- 1 cup brown sugar, firmly packed
- 2 teaspoons vanilla extract
- 1/2 teaspoon salt
- 1/3 cup flour
- 1/3 cup creamy peanut butter (not natural-style)
Pre-heat the oven to 300°F.
Spray an 8-inch baking pan with cooking spray, line with parchment paper, and spray the paper lightly to coat. Melt the chocolate and butter in the microwave, stopping frequently to stir and checking to prevent scorching. Once the chocolate mixture is melted and smooth, whisk in the eggs, sugar, vanilla and salt. Whisk in the flour; stir until just combined and transfer to prepared baking pan.
Place the peanut putter in a quart-size resealable plastic bag and snip off one corner. Squeeze the peanut butter into the cut corner of the bag and twist the bag closed. Pipe the peanut butter in four long, straight lines across the top of the batter. Using a butter knife, swirl the peanut butter into the batter, so it looks marbled.
Bake until a knife comes out just clean from a a middle chocolate portion – the peanut butter swirl will not look dry – 40-45 minutes. Do not overcook!
Let the brownies cool completely, then cut into small squares. Store in the refrigerator for up to one week.