• Preheat oven to 350°F/175°C. Grease a 9×13 inch pan and line with parchment paper.
• In a medium bowl whisk the flour and baking powder together
• In a small saucepan, melt the butter. Let the butter begin to brown, once it gives off a nutty, toasty smell with brown flecks at the bottom, take it off the heat. Add the sugars, vanilla, coffee and salt and combine. Let it cool to room temperature.
• Add the eggs and whisk until combined.
• Pour the butter mixture into a large bowl and add the flour mixture. Stir until just combined – don't overmix it!
• In a small bowl, microwave the peanut butter and butter together until smooth and creamy.
• Pour the batter into the prepared pan. Drop 5 large dollops of the peanut butter filling and use a butter knife to swirl it around the top.
• Bake for 22-24 minutes, until the edges are set and the top is golden. When you insert a toothpick, you should still have a few crumbs. We don't want to overbake it!
• Transfer to a wire rack and let it cool completely. Cut into bars.

Mocha Drizzle

• Melt dark chocolate in a microwave in 15 second bursts
• Add icing sugar, water and espresso powder and mix until smooth.
• Drizzle on to cooled blondies