Line an 8x8 or 9x9-inch baking dish with parchment paper, overlapping the sides of the pan. Then set it aside 'til you're ready for it; that way it's ready to go.
In a large mixing bowl or using a mixer, mix together the butter, vanilla extract, peanut butter, and powdered sugar.
Add in the graham cracker crumbs, and mix well.
Spread the peanut butter mixture into the paper lined baking dish, and press it into a fairly smooth and even layer.
Add the chocolate chips to a microwave-safe measuring cup or bowl and melt, starting at 30 seconds, then stirring every 15-20 seconds, 'til melted and smooth.
Spread the melted chocolate mixture over the peanut butter layer.
At this point, you can immediately chill in the fridge for at least 2 hours or until the bars are firm; or you can wait until the chocolate has just about set at room temperature, and cut into bars before chilling. When you're ready to serve your no bake chocolate peanut butter bars, just lift them out of the pan by the paper, peel it back, slice the bars, and serve.