Start by lining your 8x8 inch baking pan with parchment paper. Leave some overhang on the sides to make it easier to lift the bars out once they’re set.
In a large mixing bowl, combine the melted butter, granulated sugar, and eggs. Whisk until smooth. Add in the graham cracker crumbs, shredded coconut, and cocoa powder. Stir until everything is well combined. Press this mixture firmly into the bottom of your prepared baking pan to create an even layer.
In another bowl, combine the creamy peanut butter and unsalted butter. Beat together until creamy and smooth. Gradually add the powdered sugar, mixing until combined. Pour in the milk and continue to mix until the filling is smooth and spreadable.
Spread the peanut butter filling evenly over the chocolate base layer in your baking pan. Use a spatula to smooth it out, ensuring it's even and reaches all corners.
In a double boiler or a microwave-safe bowl, melt the chopped semisweet chocolate along with the two tablespoons of unsalted butter. Stir until smooth and fully melted.
Pour the melted chocolate over the peanut butter layer, spreading it evenly with a spatula. Tap the pan gently on the counter to eliminate any air bubbles.
Refrigerate the bars for at least 2 hours, or until they are firm and set. This step is crucial for achieving the perfect texture.
Once set, lift the bars out of the pan using the parchment paper overhang. Use a sharp knife to cut them into squares. Serve chilled or at room temperature, and enjoy the deliciousness of Peanut Butter Nanaimo Bars!
