Line the bottom and sides of a 8, 9, or 10-inch spring-form pan with parchment paper. Use a fork to combine the peanut butter Oreo crumbs together with the melted butter in a small mixing bowl. Stir this until everything is evenly moistened. Firmly press the mixture evenly across the bottom and up the sides of the spring-form pan.

In the bowl of a stand mixer fitted with a whisk attachment or in a mixing bowl using a hand mixer, beat the cream cheese, peanut butter, brown sugar, and vanilla extract until smooth and lightened in texture. Pour in the heavy cream and whip until smooth and fluffy. Pour into the Oreo crust and smooth the top. Put the pie in the freezer while you prepare the ganache.

Add the heavy cream and dark or bittersweet chocolate to a microwave-safe 2 quart bowl. Heat on HIGH for 3 minutes then let stand for 5 minutes. After 5 minutes, use a whisk to slowly stir the ganache in a circular pattern in one direction until it becomes shiny, about 3 minutes. Do not BEAT the ganache, just slowly stir it. Don't worry, it'll come together. Let the ganache stand for 15 minutes at room temperature, stirring once or twice. Pour the finished ganache over the peanut butter filling. Shake the pie gently from side to side to distribute the ganache evenly. Return the pie to the freezer until the ganache is firmed up.

Add the confectioner's sugar to the heavy cream in the bowl of a stand mixer fitted with a whisk attachment or in a large mixing bowl. Slowly stir the confectioner's sugar in until the sugar is dissolved then raise the speed of the mixer (or hand mixer) to HIGH and whip the cream to stiff peaks. Dollop it over the surface of the ganache then spread it evenly to the edges of the crust.

Scatter 1/4 of the Reese's Minis over the top of the whipped cream layer. Roughly chop the remaining Reese's Minis then scatter those over the surface of the pie. Lightly cover with plastic wrap and return the pie to the freezer for at least 5 hours or overnight.

Loosen the outer ring of the spring-form pie and remove it. Use the excess parchment paper to lift one edge of the bottom of the pie from the base of the spring-form pan. Slide your hand between the parchment and the pan base and lift the pie. Peel back the parchment from the bottom of the pie as you place it on a serving plate or platter or cake plate. Drizzle the chocolate syrup over the top of the pie.

Run hot water over a large, sharp knife then wipe it dry with a clean towel. Slice the pie into wedges, running water over the knife to reheat it and wiping clean as needed to get neat slices. Serve immediately or let stand at room temperature to soften for up to 30 minutes.

Store leftover pie, well wrapped with plastic wrap, in the freezer for up to a month.