Oreo cookies (without toppings) put into a blender and chop into a crumb.
Add some milk and mix. The mass should be like a plasticine and not be too sticky (a lot of milk).
Press onto the bottom of a greased 9-in. springform pan; set aside.
In a large bowl, beat the cream cheese, sugar and flour until smooth.
Add eggs; beat on low just until combined.
Stir in vanilla and melted chocolate just until blended. Pour filling over crust.
Bake at 350° for 40-45 minutes or until center is almost set.
Cool on a wire rack for 10 minutes.
Carefully run a knife around edge of pan to loosen; cool 1 hour longer. Refrigerate overnight.