2 large egg whites
6 digestive biscuits, finely crushed
4 sheets leaf gelatin
150g frozen red berries, defrosted
3 level tbsp sweetener
200g plain quark
400g fat-free natural Greek-style yogurt
1 Preheat your oven to 190°C/ fan 170°C/gas 5. Line a baking tray with baking paper and place 4 deep individual pastry rings (8-9cm in diameter) on top.
2 Beat the egg whites in a clean glass bowl until frothy and add the crushed biscuits, stirring to combine. Divide between the rings, pressing down with the back of a spoon to make an even base. Bake for 12-15 minutes, then set aside to cool completely. Once cool, pop the whole tray in the freezer while you prepare the filling.
3 Soak the gelatine in a bowl of cold water for 10-12 minutes, or until softened. Meanwhile, put the berries and 1 tbsp sweetener into a mini food processor and whizz until smooth. Press through a sieve into a measuring jug. Reserve half of the sieved juice and pour the remaining juice into a small saucepan with 2 tbsp water. Bring just to the boil, then remove from the heat. Squeeze the water from the softened gelatine and add the gelatine to the pan. Stir until dissolved, then set aside to cool.
4 Whisk together the quark, remaining sweetener and yogurt. Add the berry gelatine mixture and whisk together. Pour evenly over the prepared cheesecake bases. Drizzle the remaining sieved juice over the top of each one and use a skewer to swirl the top, creating a marbled effect. Freeze for 20 minutes, then transfer to the fridge for 4-6 hours, or until set.
5 To serve, very briefly blast the sides of each ring with a cook’s blowtorch or hairdryer (making sure the rings don’t get too hot), then carefully lift off to reveal the cheesecakes.