Blitz the biscuits in a food processor to a fine crumb, or mash them up in a bag and add the melted butter – pulse a few times until it is combined well.
Tip into an 8″/20cm deep springform tin and press down firmly – chill in the refrigerator whilst you do the rest!
For the Cheesecake Filling
Place your custard creams around the edge of the tin. You can gently push them slightly into the biscuit base to help them stay in place for now.
In your stand mixer/large bowl, add your cream cheese and icing sugar, and whip till smooth.
Add in the double cream, custard flavouring, and vanilla extract and whip till really thick.
Spread into the middle of the biscuit circle, and smooth over the top.
Leave your cheesecake to set in the fridge for 5-6 hours, or preferably overnight.
For the Decoration
Remove your cheesecake from the tin!
Whip together the double cream and icing sugar, and pipe onto your cheesecake. I used a 2D closed star tip.