Preheat the oven to 350 degrees, and line the bottom of an 8-inch square baking dish with parchment. Put three-fourths of the cookies into a food processor and blitz to a crumb. Add the melted butter and process until combined. Pour into the prepared pan and smooth over with the back of a spoon.
Put the cream cheese, vanilla paste, powdered sugar and eggs into a mixing bowl and whisk to combine. Pour on top of the cookie base and use an offset spatula to smooth. Break up the remaining cookies and arrange on top, then bake for 40 minutes until set but not firm. Cool to room temperature then put into the fridge for 2 hours before slicing into bars.