To make the base use a food processor to whizz up the biscuits into crumbs, or gently crush them with a rolling pin in a bowl
Mix the melted butter into the biscuits crumbs and press the mixture into the bottom of a 23cm springform tin. Put it in the fridge for 30 minutes to set
For the cheesecake filling use an electric food mixer with a whisk attachment or an electric hand whisk to mix together the cream cheese, icing sugar and cocoa powder until smooth with no lumps
Add the double cream and whisk until it is very 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
Gently fold in the bashed up Crunchie bars
Smooth the mixture 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 from the tin and put on your serving plate. Smooth the sides with a butter knife to create a neater finish
Drizzle over the melted milk chocolate, using either a piping bag or a spoon
Whip up the double cream with the icing sugar and vanilla, and pipe it all around the edges of the cheesecake
Decorate with the Crunchie chunks around the edge, and crushed Crunchie in the middle
Serve immediately, store any leftovers in the fridge and eat within 2-3 days