Line an 8x8-inch baking dish with parchment paper. Leave edges hanging for easy removal later.

In a bowl, combine melted butter, graham cracker crumbs, powdered sugar and peanut butter. Mix until smooth.

Transfer mixture into prepared pan. Use spatula to press evenly into the bottom for a firm, flat base.

Place pan in refrigerator for 15-20 minutes. Chilling makes base firm and easier to top with chocolate.

In a saucepan or microwave-safe bowl, melt chocolate chips with peanut butter. Stir until smooth and glossy.

Pour melted chocolate mixture over chilled base. Use spatula to spread evenly, covering entire surface.

Return pan to refrigerator. Chill for at least 2 hours or until chocolate topping sets completely.

Lift bars out using parchment paper. Use a sharp knife to cut into squares or rectangles.

Arrange bars on a plate. Serve chilled or at room temperature for soft, creamy bites.

Enjoy rich, chocolatey, and peanut buttery bars as a snack, dessert or party treat.