Line the base of a 23cm loose-bottomed cake tin with a round of greaseproof paper or baking paper. Set aside.

Pop 200g digestive biscuits into a bowl and use the end of a rolling pin or the bottom of a jam jar to crush them. If you have a food processor, you can whizz the biscuits in it to blitz them into crumbs.

Tip the butter into a small bowl and microwave for 1 min to melt it. No microwave? Put the butter in a small pan and melt it over a low heat. Pour the butter into the biscuit crumbs and use a flexible spatula to stir them together. If the biscuit crumbs are in a food processor, just whizz a few times with the butter to combine. Scoop the buttery crumbs into the cake tin, then level the top with the back of a spoon. Transfer the tin to the fridge and chill for 1 hr.

When the base has chilled for 1 hr, pour the double cream into a mixing bowl and whisk until soft peaks form. Add the ricotta and gently fold together with a spatula to combine. Fold in 2 tbsp caster sugar. Finely grate in the zest from both clementines and squeeze in the juice from 1. Gently fold to combine. Scoop the ricotta mixture into the cake tin and spread to cover the biscuit base. Return to the fridge and chill for 4 hrs or overnight.

Run a palette knife around the edge of the cheesecake. Lift the base out of the cake tin then use the palette knife to slide the cheesecake onto a serving plate. Top with the chocolate penguins. Serve in slices. The cheesecake is best eaten within 3 days of making.