In a medium bowl, combine the graham cracker crumbs, melted butter, and granulated sugar. Stir together until the mixture resembles wet sand. Firmly press the mixture into the bottom and up the sides of a 9-inch tart pan or pie dish. Place the crust in the refrigerator while preparing the ganache.

In a microwave-safe bowl, combine the milk chocolate chips and vegetable oil. Microwave in 30-second intervals, stirring after each, until the mixture is fully melted and smooth. Pour half of the ganache into the prepared crust, spreading it evenly with a spatula. Return the pie to the refrigerator and chill for at least 2 hours or until the ganache is fully set.

In a separate mixing bowl, beat together the creamy peanut butter, powdered sugar, vanilla extract, and a pinch of salt until smooth and fluffy. Spread the peanut butter mixture evenly over the chilled ganache layer. Place the pie back in the refrigerator while preparing the final ganache layer.

Reheat the remaining ganache gently if it has thickened, until it is spreadable. Carefully pour the ganache over the peanut butter layer, smoothing the top with a spatula. If desired, drizzle additional melted peanut butter on top and sprinkle with chopped Reese’s Peanut Butter Cups for garnish.

Refrigerate the pie for at least 4 hours, or preferably overnight, to allow the layers to fully set and for clean slicing.

When ready to serve, use a sharp knife dipped in warm water and wiped dry between cuts to create neat slices. Serve chilled and enjoy the rich, layered flavors.