1. In a large mixing bowl, combine the creamy peanut butter, melted butter, powdered sugar, and graham cracker crumbs. Stir until fully combined into a smooth, thick mixture.
2. Press this peanut butter mixture evenly into the bottom of a 9×13-inch baking dish lined with parchment paper. Use the back of a spoon to smooth out the surface.
3. In a microwave-safe bowl, combine the chocolate chips and heavy cream. Microwave in 30-second intervals, stirring in between, until the chocolate is fully melted and smooth.
4. Pour the chocolate mixture over the peanut butter layer, spreading it evenly with a spatula.
5. Refrigerate the bars for at least 2 hours, or until the chocolate is set and firm to the touch.
6. Once set, lift the bars out of the dish using the parchment paper. Cut into squares and enjoy!

A quick tip from my kitchen to yours: when pressing the peanut butter mixture into the dish, use a piece of parchment paper to prevent it from sticking to your fingers.