In a large bowl, mix together the melted butter, peanut butter, and vanilla extract until smooth.

Gradually add in the confectioners’ sugar and graham cracker crumbs, stirring until everything is well combined. The mixture should be thick and sticky.

Line a 9x9-inch square pan with parchment paper for easy removal. Press the peanut butter mixture into the pan, making sure it’s even and compact. I find using the back of a spoon or my fingers helps smooth it out perfectly.

In a microwave-safe bowl, heat the chocolate chips and peanut butter in 30-second intervals, stirring in between, until fully melted and smooth.

Pour the melted chocolate mixture over the peanut butter base, spreading it evenly with a spatula. Sprinkle a pinch of flaky sea salt over the top if you like that sweet-and-salty contrast.

Refrigerate the bars for at least 2 hours, or until the chocolate has hardened and the bars are firm. If you're in a rush, you can speed up the process by putting them in the freezer for 30-60 minutes.

Once set, lift the bars out of the pan using the parchment paper and cut them into squares. These bars are perfect for a snack, dessert, or even a treat to bring to your next party!