1 Heat the oven to 180°C (160°C in a fan oven), 375°F, gas 5. Butter 4 small baking tins (approx. 8 cm in diameter).
2 Cream the butter and sugar together. Add the eggs one by one, beating after each addition. Add the quark, cream cheese, a little vanilla, the lemon zest and a pinch of salt and stir to combine. Mix the cornflour with the baking powder and stir into the mixture. Spoon the mixture into the tins and bake in the oven for around 20 minutes - the cheesecakes should not colour too much.
3 Turn off the oven and leave the cheesecakes in the oven to rest for a further 10 minutes, then remove from the oven, carefully turn out of the tins and leave to cool.
4 For the sauce, whisk the cornflour with 2 tbsp cherry juice. Bring the remaining juice to the boil with the sugar. Stir in the cornflour mixture and bring to the boil. Stir through the cherries, remove from the heat and leave to cool.
5 Serve the cheesecakes drizzled with a little cherry sauce.