Ingredients:
- ½ cup (1 stick / 113g) unsalted butter, melted
- 1 cup (200g) granulated sugar
- 2 large eggs
- 1 teaspoon (5ml) vanilla extract
- ⅓ cup (30g) unsweetened cocoa powder
- ½ cup (60g) all-purpose flour
- ¼ teaspoon (1.5g) salt
- ¼ teaspoon (1g) baking powder
- ½ cup (128g) creamy peanut butter
- 12-16 mini peanut butter cups (or 6 regular-sized, chopped)
- ½ cup (85g) chocolate chips (semi-sweet or dark) (optional)
Instructions:
- Preheat oven to 350°F (175°C). Line a 9x9 inch baking pan with parchment paper or grease well.
- In a large bowl, whisk melted butter and sugar until smooth.
- Add eggs and vanilla; mix until well combined.
- In the same bowl, stir in cocoa powder, flour, salt, and baking powder until just combined – be careful not to overmix.
- Pour half the batter into the prepared pan and spread evenly.
- Gently warm peanut butter in the microwave for 10-15 seconds until easily drizzled. Drizzle half the peanut butter over the batter.
- Press peanut butter cups evenly into the batter.
- Pour remaining batter over the top, and smooth evenly.
- Drizzle remaining peanut butter on top. Use a knife or skewer to swirl the peanut butter into the top layer.
- Bake for 30-35 minutes. Check doneness with a toothpick – it should come out with a few moist crumbs attached.
- Let cool completely in the pan before cutting into squares.