Step 1: Prepare the Crust : Preheat your oven to 325°F (165°C) and line an 8x8-inch baking pan with parchment paper, leaving an overhang for easy lifting. In a bowl, combine chocolate cookie crumbs, sugar, and melted butter. Mix until the crumbs are evenly coated and resemble wet sand. Press firmly into the bottom of the prepared pan to form a compact crust. Bake for 8–10 minutes, then remove from the oven and let cool while preparing the filling.

Step 2: Make the Peanut Butter Cheesecake Filling : In a large bowl, beat cream cheese, peanut butter, granulated sugar, and brown sugar together until smooth and creamy (about 2–3 minutes). Add eggs, one at a time, beating on low speed just until combined. Mix in vanilla extract and sour cream until the mixture is silky and uniform. Pour the cheesecake filling over the cooled crust, smoothing the top with a spatula.

Step 3: Bake the Cheesecake : Bake in the preheated oven for 30–35 minutes, or until the edges are set but the center still has a slight jiggle. Remove from the oven and let it cool to room temperature (about 1 hour). Refrigerate for at least 3 hours or overnight to fully chill and set.

Step 4: Prepare the Chocolate Ganache : In a small saucepan, heat heavy cream over medium-low heat until it just begins to simmer (don’t boil). Pour the hot cream over chocolate chips in a heatproof bowl. Let it sit for 2 minutes, then whisk until smooth and glossy. Stir in butter for added shine if desired. Allow the ganache to cool for 5–10 minutes before pouring over the chilled cheesecake layer. Spread evenly and smooth the top.

Step 5: Chill and Slice : Return the pan to the refrigerator and chill for another 30–60 minutes, until the ganache is set. Use the parchment paper overhang to lift the bars from the pan. Slice into 12 even bars using a sharp knife (wipe the blade between cuts for clean edges).