Maltesers cheesecake

For the base: Butter a 20 cm spring form pan with melted butter. Whizz the base ingredients in a blender until they are like fine breadcrumbs. Pour this crumb mixture into a bowl and add the melted butter. Mix everything together then tip into the spring form pan. Press it down so it is level and compact with the back of a large spoon then put the tin in the fridge for a good 30 mins to firm up. For the topping: Put the cream cheese, sour cream, icing sugar and vanilla in a bowl and beat together until combined. In another bowl whisk the double cream until to a medium peak. Pour the whipped cream in a bowl with the cream cheese, sour cream, icing sugar and vanilla and fold gently together. Add the crushed Maltesers and fold to combine. To assemble: Take the tin containing the biscuit base from the fridge and tip the creamy mixture over the top of it. Spread it around to level and then bang the tin a couple of times on the work surface to make sure it touches the base mixture evenly and there are no gaps. Place in the fridge for an hour or two to set. Once ready to serve, remove from the fridge and press the Maltesers into the topping if using. Cut and serve.