Prepare Your Pan: Lightly grease a 9-inch tart pan (preferably one with a removable bottom) and line the bottom with a circle of parchment paper.
Melt Chocolate for Shell: In a microwave-safe bowl, combine the chocolate chips and vegetable oil. Microwave for 45-55 seconds, then stir until the chocolate is completely melted and smooth.
Create the Chocolate Shell: Pour half of the melted chocolate into your prepared tart pan. Use a spoon or spatula to spread it evenly over the bottom and up the sides. Place the pan in the fridge to chill while you make the filling.
Mix Dry Filling Ingredients: In a large bowl, whisk together the powdered sugar and graham cracker crumbs. Set aside.
Melt Wet Filling Ingredients: In another microwave-safe bowl, combine the crunchy peanut butter and salted butter. Microwave for 45 seconds, then stir until smooth and well combined.
Combine Filling: Pour the warm peanut butter mixture over the dry ingredients (powdered sugar and graham cracker crumbs). Stir well until the mixture is fully incorporated and starts to come together.
Assemble the Pie: Take your chilled chocolate shell from the fridge. Evenly press the peanut butter mixture into the chocolate shell. If your remaining chocolate has thickened, briefly microwave it for 15-20 seconds until smooth again. Spread this chocolate over the peanut butter layer, smoothing it to the edges. Gently tap the pan on the counter to ensure the top layer is level.
Chill to Set: Refrigerate the pie for at least 4 hours, or ideally overnight, until it's firm and perfectly set.
Serve and Enjoy: When ready to serve, remove the pie from the fridge and let it sit at room temperature for about 20 minutes. This makes it easier to slice cleanly. Carefully remove it from the tart pan, place it on a serving platter, slice with a warm, sharp knife, and dig in!