Want to practice your new baking skills? Try this go-to recipe for homemade outrageously irresistible brownies. Dollops of peanut butter filling are spooned onto brownie batter; pulling a knife back and forth through both results in a marbleized look.

Yields: 9 large or 16 small squares

Ingredients

Batter:
8 tablespoon(s) (1 stick) unsalted butter, cut into small pieces, plus more for pan
2 ounce(s) good-quality unsweetened chocolate, coarsely chopped
4 ounce(s) good-quality semisweet chocolate, coarsely chopped
2/3 cup(s) all-purpose flour
1/2 teaspoon(s) baking powder
1/4 teaspoon(s) salt
3/4 cup(s) granulated sugar
3 large eggs
2 teaspoon(s) pure vanilla extract

Filling:
4 tablespoon(s) unsalted butter, melted
1/2 cup(s) confectioners’ sugar
3/4 cup(s) smooth peanut butter
1/4 teaspoon(s) salt
1/2 teaspoon(s) pure vanilla extract

Directions

1. Preheat oven to 325 degrees F. Butter an 8-inch square baking pan and line with parchment, allowing a 2-inch overhang. Butter lining (not overhang).

2. Make batter: Put butter and chocolates in a heatproof medium bowl set over a pan of simmering water; stir until melted. Let cool slightly. Whisk together flour, baking powder, and salt in a bowl.

3. Whisk granulated sugar into chocolate mixture. Add eggs, and whisk until mixture is smooth. Stir in vanilla. Add flour mixture; stir until well incorporated.

4. Make filling: Stir together butter, confectioners’ sugar, peanut butter, salt, and vanilla in a bowl until smooth.

5. Pour one-third of batter into prepared pan; spread evenly with a rubber spatula. Drop dollops of peanut butter filling (about 1 tablespoon each) on top of batter, spacing about 1 inch apart. Drizzle remaining batter on top, and gently spread to fill pan. Drop dollops of remaining filling on top. Gently swirl peanut butter filling into batter with a butter knife, running the knife lengthwise and crosswise through layers.

6. Bake until a cake tester inserted into brownies (avoid center and edges) comes out with a few crumbs but is not wet, about 45 minutes. Let cool slightly in pan, about 15 minutes. Lift out; let cool completely on a wire rack before cutting into squares. Brownies can be stored in an airtight container at room temperature up to 3 days.