- 1/2 cup confectioners’ sugar
- 1/3 cup creamy or crunchy peanut butter, such as Jif
- 5 tablespoons unsalted butter, divided, plus more for pan
- 2 tablespoons whole milk
- 1/2 teaspoon plus a pinch of kosher salt (we use Diamond Crystal)
- 1 cup bittersweet chocolate chips, divided
- 1/2 cup granulated sugar
- 1 large egg
- 1 tablespoon Dutch-process cocoa powder
- 1/2 teaspoon pure vanilla extract
- 1/2 cup unbleached all-purpose flour
- Preheat oven to 350°F. Sift confectioners’ sugar into a bowl. In a small, heavy saucepan, heat peanut butter, 1 tablespoon butter, milk, and pinch of salt over medium-low, stirring often, until just melted and combined. Pour over confectioners’ sugar and stir to combine.
- Butter a standard (8 1/2-by-4 1/2-inch) loaf pan and line with parchment, leaving a slight overhang on long sides. Melt remaining 4 tablespoons butter and 2/3 cup chocolate chips in a heat-proof bowl set over (but not in) a pot of simmering water, stirring until smooth, 3 to 4 minutes. Remove from heat and add granulated sugar; whisk vigorously 1 minute. Whisk in egg vigorously until mixture is glossy, another 1 minute.
- Whisk in cocoa, vanilla, and remaining 1/2 teaspoon salt. Fold in flour and remaining 1/3 cup chocolate chips. Dollop half of brownie batter into prepared pan and spread with a spoon or offset spatula to reach edges. Dollop peanut-butter mixture over top and spread in an even layer. Top with remaining brownie batter and spread to reach edges.
- Bake until center is set and edges pull away from pan, about 30 minutes. Let cool completely, about 1 hour, before lifting out of pan and slicing. Brownies can be stored in an airtight container at room temperature or refrigerated up to 3 days.
Notes:
To ensure that coveted crackly top, mix the batter until it’s glossy.