Line an 8x8 inch baking pan with aluminum foil or parchment paper and spray with cooking spray.
1. In a medium microwave-safe bowl, melt butter and add confectioners' sugar and brown sugar. Mix with a rubber spatula to combine. Add graham cracker crumbs and give it a good stir. Last but not least, add creamy peanut butter and stir until smooth and thoroughly combined. Spread in an even layer in the prepared baking pan. Set aside.
2. In another bowl, melt 3/4 cup chocolate chips and add 2 tablespoons creamy peanut butter, stir until melted. Spread over peanut butter bars. Next, heat 1/4 cup peanut butter in the microwave for 20-30 seconds (it helps with the pouring). Drizzle peanut butter over the chocolate, creating 5-6 straight lines. Rotate pan 90 degrees and using a toothpick, drag it through the lines, creating the pattern. Repeat 5-6 times. Cover pan and refrigerate for at least 2 hours before cutting. Enjoy!