Prepare the pan: Line the bottom of a 9-inch springform pan with parchment.
Lightly grease the sides to help clean release.
Make the crust: In a bowl, mix cookie crumbs, melted butter, sugar, and a pinch of salt until the texture resembles wet sand. Press firmly into the bottom and 1 inch up the sides of the pan. Use a flat-bottomed glass for an even layer.
Chill while you make the filling.
Whip the cream: In a cold bowl, whip the heavy cream to stiff peaks. Set aside. This will keep the filling light and airy.
Beat the base: In another bowl, beat softened cream cheese until smooth and lump-free.
Add peanut butter, powdered sugar, vanilla, and salt. Beat until creamy and well combined. Scrape down the bowl to avoid streaks.
Fold it together: Gently fold the whipped cream into the peanut butter mixture in two additions.
Keep strokes soft to avoid deflating the cream. The mixture should be thick but spreadable.
Fill the crust: Spoon the filling into the chilled crust and smooth the top with an offset spatula. Tap the pan lightly on the counter to settle any air pockets.
Chill for at least 4 hours, preferably overnight, until set.
Make the ganache: Heat heavy cream just to a simmer. Pour over chocolate (and butter, if using) in a bowl. Let sit 2 minutes, then stir until silky.
Cool 10–15 minutes until slightly thickened but still pourable.
Top the cheesecake: Pour ganache over the chilled cheesecake, tilting the pan for an even layer. Add garnishes while the ganache is still soft. Chill 30–45 minutes until the top is set.
Unmold and serve: Run a thin knife around the edge, then release the springform ring.
Slice with a warm, clean knife, wiping between cuts for neat pieces.