Preheat oven to 325°F (163°C). Crush 24 Oreo cookies and mix with melted butter until wet sand-like. Press into the bottom of a greased 9x9-inch pan.

Beat softened cream cheese with sugar until smooth. Gradually add eggs one at a time, mix in sour cream and vanilla until creamy.

Chop remaining 16 Oreos and fold into the batter gently while keeping the cookie bits intact.

Pour filling over the crust and spread evenly. Bake for 40-45 minutes until edges are set and center jiggles slightly.

Cool for 1 hour at room temperature, then chill for at least 4 hours or overnight.

Slice into squares with a warm damp knife for clean edges. Serve chilled.