Preheat your oven to 325°F (160°C). Line a 9×13-inch baking pan with parchment paper, leaving some overhang on the long sides to form a sling. Lightly grease the parchment and sides of the pan with butter or nonstick spray.

In a food processor, pulse 24 Oreo cookies until you have fine, even crumbs. Transfer to a bowl and stir in the melted butter and granulated sugar (if using) until the crumbs are evenly moistened and resemble wet sand.

Pour the crumb mixture into the prepared pan. Use the bottom of a measuring cup or glass to press it firmly and evenly across the bottom. Bake for 8–10 minutes, just until set and fragrant. Remove from the oven and let the crust cool slightly while you prepare the cheesecake filling.

In a large mixing bowl with a stand mixer or hand mixer, beat the softened cream cheese on medium speed for 1–2 minutes until completely smooth, scraping down the sides of the bowl. Add the sugar and beat for another 1–2 minutes until creamy and well combined.

Add the eggs one at a time, mixing on low speed after each addition just until combined. Avoid beating on high speed or incorporating too much air, which can contribute to cracking.

On low speed, mix in the sour cream, vanilla extract, and salt until smooth. Scrape down the bowl and give the batter one last gentle mix. It should be thick, glossy, and free of lumps.

Gently fold 12–16 roughly chopped Oreo cookies into the batter with a spatula. Aim for visible chunks throughout—don’t overmix or the pieces will disappear.

Pour the cheesecake mixture over the slightly cooled Oreo crust, smoothing the top with a spatula. Gently tap the pan on the counter once or twice to release any large air bubbles.

Bake at 325°F (160°C) for 30–35 minutes, or until the edges are set and slightly puffed and the center still has a slight jiggle when you gently shake the pan. The center should look like set custard, not liquid.

Turn off the oven and crack the door open slightly. Let the cheesecake bars sit in the warm oven for about 15 minutes to cool gradually. Transfer the pan to a wire rack and let it come to room temperature. Cover and refrigerate for at least 4 hours, preferably overnight, until fully chilled and set.

Once fully chilled, use the parchment overhang to lift the slab of cheesecake out of the pan. Sprinkle the top with crushed or chopped Oreos, if desired. Use a long, sharp knife to slice into 24 small bars or 16 larger bars, wiping the knife with a warm, damp cloth between cuts for clean edges. Serve plain or with whipped cream and a drizzle of warm chocolate sauce or melted chocolate.