Method
Put the biscuits into a blender and zap briefly to get crumbs (or put them in a plastic food-storage bag, knot it shut and then crush the biscuits into crumbs with a rolling pin). Line a 12-hole bun tin with 12 paper cupcake cases. Next, place a saucepan over a medium-low heat, add the butter and let it melt. When the butter has all melted, take the pan off the heat and sieve in half of the cocoa powder, then add all the biscuit crumbs and stir until well combined. Divide the mixture equally between the bottoms of the cupcake cases, pressing it down with the back of a spoon. Put the tin in the fridge to chill for about 15 minutes - towards the end of this time, preheat the oven to 180°C (Gas Mark 4). While the cheesecake bases chill, make the filling. Put the soft cheese into a mixing bowl and sieve in the rest of the cocoa, then beat together to mix. Add the sugar, beaten egg and vanilla extract, then fold it all together gently until well combined, without any streaky bits. Take the tin out of the fridge and spoon the filling into the cupcake cases, on top of the chilled biscuit crumbs, sharing it out equally. Put the tin into the hot oven and bake for 10-12 minutes, until the filling is just set, then place the tray on a wire rack and leave to cool completely. To decorate, use a potato peeler to shave curls of the 30g of your chosen chocolate (or just grate it) on to the tops of the cakes, then add the chocolate mini-eggs for the perfect finishing touch.