- 1/2 cup (1 stick) unsalted butter
- 3/4 cup granulated sugar
- 2 eggs
- 1 teaspoon vanilla
- 1 cup all-purpose flour
- 1/3 cup smooth or crunchy peanut butter
- 3 ounces semi-sweet chocolate, melted
- Preheat oven to 350°F. Line a 8x8-inch baking pan with foil leaving 1-inch overhang on ends; coat bottom with cooking spray or butter.
- Melt butter in a saucepan or microwave-safe bowl in microwave. Stir in sugar, eggs and vanilla. Blend in flour until smooth.
- Measure 3/4 cup batter into a separate bowl; stir in peanut butter. Stir melted chocolate into remaining batter.
- Drop half the peanut butter batter by tablespoonfuls about 1 inch apart in prepared pan. Spread chocolate batter over; dollop remaining peanut butter batter on top. Run a table knife through batter lengthwise and crosswise a few times to swirl peanut butter. Bake 25 minutes or until pick inserted in center comes out clean.