This is my favourite cheesecake recipe, which DH even had as his birthday cake earlier this year! It's adapted from a BBC recipe...
200g/7oz chocolate chip biscuits
75g/2½ oz unsalted butter
400g/14oz full-fat cream cheese, at room temperature
300g/10½ oz mascarpone, at room temperature
200g/7oz icing sugar, sifted
1 tsp vanilla extract
1 punnet raspberries plus extra for decorating
2 squares chocolate for decorating
chopped hazelnuts for decorating (optional)
Line a 23cm springform tin with baking parchment/greaseproof paper (not essential, but makes it easier to get the cheesecake off the base later)
Place the biscuits into a sealable freezer bag. Push all the air out and seal the bag. Crush the biscuits with a rolling pin, being careful not to break any holes in the bag.
Melt the butter in a large saucepan. Tip the biscuit crumbs into the butter and mix well until thoroughly combined. Press the buttery crumbs into the bottom of the tin. Chill in the refrigerator while you make the topping.
Combine the cream cheese and mascarpone in a large mixing bowl. Using an electric handheld mixer, blend the cheeses together until light and fluffy. Add the icing sugar a little at a time and blend to incorporate. Finally, mix in the vanilla. The mixture should be very light and fluffy. Fold in the raspberries - it doesn’t matter if some of them get squashed - it makes a nice marbled effect through the cheesecake.
Spread the cream cheese mixture over the biscuit base and smooth the top with a palette knife or spatula. Cover with cling film and chill in the fridge overnight (it says 4 hours in the original recipe, but I really don’t think this is long enough).
To decorate, run a palette knife around the inside of the tin to loosen the sides away from the cheesecake and remove from the tin. Place on a plate. Melt the chocolate (dark or light or a mixture - doesn’t matter) and then, using a teaspoon, drizzle over the top of the cheesecake. Sprinkle chopped hazelnuts to taste over the cheesecake and then top with raspberries.
Put it back in the fridge till you’re ready to serve it.