Preheat the oven to 350 degrees F.
Mist a 9x9-inch baking pan with non-stick spray and line with parchment. Place the chocolate sandwich cookies in the bowl of a food processor and pulse until finely ground.
Add the melted butter to the ground cookies and toss together with a fork until combined.
Press the mixture in an even layer over the bottom of the prepared pan.
Place the cream cheese, sugar, cornstarch, and salt in a large mixing bowl and beat on medium speed until smooth and creamy.
Scrape the bottom and sides of the bowl with a silicone spatula, then stir in the eggs, one at a time, scraping the bottom and sides of the bowl with a silicone spatula after each addition.
Stir in the cream, coffee liqueur, and vanilla, and transfer the mixture to the prepared pan.
Bake for 20 minutes at 350 degrees F, then reduce the oven temperature to 250 degrees F and continue to bake for one hour, or until set around the edges and still slightly wobbly towards the center.
Chill overnight before removing from the pan and cutting into squares.
Garnish with whipped cream and cocoa powder.