To make the base use a food processor to blitz the oreo biscuits into crumbs, or bash them with a rolling pin in a bowl or a freezer bag, then put them in a mixing bowl
Pour the melted butter into the biscuit crumbs and mix them in. Press the mixture into the bottom of a 23cm springform tin until compact and even. Put it in the fridge for 30 minutes to set
For the cheesecake filling use a food mixer with a whisk attachment or an electric hand whisk to mix together the cream cheese, vanilla extract and icing sugar until smooth with no lumps
Add the double cream and whisk until it is thick and holds it's shape. You want it to get to a stage where you can scoop some up with your spatula or spoon and you have to give it a tap on the side of the bowl or slight flick of the wrist to get the mixture off the spoon. If it’s sloppy and slides right off the spoon without any encouragement needed, then you need to mix it more
Use a food processor to blitz the oreo biscuits into crumbs, or bash them with a rolling pin in a bowl or a freezer bag, then stir them into the cheesecake filling
Smooth the filling into the tin on top of the biscuit base, then put it in the fridge overnight, or for at least 4 hours, to set
Remove the cheesecake from the tin and put on your serving plate. Smooth the sides with a butter knife to create a neater finish if needed
Drizzle or pipe the melted chocolate all over the cheesecake
Whip up the double cream with the icing sugar and vanilla, ideally using an electric whisk, and pipe rosettes all around the edge of the cheesecake
Sprinkle the chopped up Oreos in the centre of the cheesecake, and place the cut in half Oreos around the edge on top of the whipped cream
Serve immediately, store any leftovers in the fridge and eat within 2 days