Instructions

• Line an 8" x 8" (20 cm x 20 cm) baking pan with aluminum foil or parchment paper, leaving an overhang for easy removal; spray the lining lightly with non-stick cooking spray.
• In a medium microwave-safe bowl, melt 1/2 cup salted butter in the microwave until fully melted (about 30–45 seconds, depending on your microwave).
• Add 3/4 cup powdered sugar and 1/4 cup brown sugar to the melted butter. Stir with a rubber spatula until combined and no dry pockets of sugar remain.
• Stir in 1 cup crushed graham crackers until evenly mixed, then stir in 1 cup creamy peanut butter until the mixture is smooth and uniform.
• Transfer the peanut butter-graham mixture to the prepared pan. Use an offset spatula or the back of a spoon to press it into an even layer across the bottom of the pan.
• In a separate microwave-safe bowl, combine 3/4 cup semi-sweet chocolate chips and 2 tablespoons creamy peanut butter. Microwave in 20–30 second increments, stirring after each increment, until the chocolate is fully melted and smooth.
• Spread the melted chocolate mixture evenly over the peanut butter layer in the pan.
• Place 1/4 cup creamy peanut butter in a small microwave-safe bowl and heat for 20–30 seconds, or until soft and pourable. Stir to smooth.
• Drizzle the warmed 1/4 cup peanut butter in 5–6 parallel lines across the chocolate layer. Rotate the pan 90 degrees. Using a toothpick, drag it through the lines once in one direction and then once in the opposite direction to create a marbled pattern.
• Cover the pan with plastic wrap and refrigerate for at least 2 hours, or until the bars are firm.
• Use the foil or parchment overhang to lift the set bars from the pan. Transfer to a cutting board and cut into bars with a sharp knife (wipe the knife clean between cuts for neater edges).