Line the bottom of a 9-inch springform pan with parchment paper if desired.

Mix the graham-cracker crumbs, melted butter, and granulated sugar until evenly moistened. Press the mixture firmly over the bottom of the pan and slightly up the sides, then refrigerate while preparing the filling.

Beat the softened cream cheese until smooth. Add the peanut butter, confectioners’ sugar, and vanilla extract, then beat until completely blended.

In a separate cold bowl, whip the cold heavy cream to stiff peaks. Gently fold it into the peanut-butter mixture in two or three additions, taking care not to overmix.

Spread the filling over the chilled crust and smooth the top. Cover and refrigerate for at least 6 hours, preferably overnight, until firm.

For optional ganache, heat the 2 tablespoons of heavy cream until hot, pour it over the chocolate chips, and let it rest for 2 minutes. Stir until smooth, cool slightly, and spread over the cheesecake.

Run a thin knife around the edge before removing the springform ring. Keep refrigerated until serving and garnish with chopped peanuts or peanut-butter cups.