Line a 9 inch dish with cling film.
Melt the butter in a pan on a low temperature. Set aside.
Place 2/3 of the Oreos in a food processor and pulse into fine crumbs. Pour in the butter and process a little more.
Spoon into the tray and place in the fridge for 30 minutes.
Heat up a little water in a saucepan.
Combine the gelatine with 60ml of cold water in a heatproof cup.
Sit the cup in the saucepan of water and stir to dissolve the gelatine.
In a large bowl, combine the cream cheese, vanilla extract, cream, sugar and the rest of the Oreos. Use a hand held blender to beat until smooth.
Gently melt the white chocolate in the microwave on 30 second blasts until melted.
Stir the gelatine mixture and the melted white chocolate into the cream cheese mixture.
Remove the base from the fridge and add the cream cheese mixture. Smooth with the back of a spoon.
Place in the fridge until set.