Ingredients
Method
1.Line a 20cm diameter loose-bottomed cake tin with tin foil. Preheat oven to 170°C (regular bake).
2.Put biscuits in a clean sealable plastic bag and crush to a fine crumb with a rolling pin. Mix biscuit crumbs and melted butter together in a bowl then press onto the base of the lined cake tin. Chill biscuit base while making the cheesecake filling.
3.Sift flour and cocoa powder together. Mix quark or cream cheese until smooth in a bowl with a wooden spoon, or on a low speed in a cake mixer. Briefly beat in sour cream and caster sugar, then vanilla extract and lemon juice. Remove bowl from cake mixer if using. Mix in one egg, then the flour and cocoa, then add the remaining two eggs, one at a time; do not beat.
4.Pour mixture into the prepared cake tin and transfer tin into a roasting pan. Fill roasting pan with hot water to halfway up the cake tin. Transfer to the oven and bake for 25-30 minutes, or until the cheesecake is slightly firmish around the sides but still has a decent wobble in the centre. Once the cheesecake is ready, turn off the oven, prop the door ajar with a wooden spoon and leave the cheesecake to cool. When completely cool, chill until required.
5.Before serving, remove cheesecake from the loose-bottomed tin and peel off the tin foil, transferring the cheesecake to a serving plate. Lightly whip the cream and spread over the top of the cheesecake. Sieve over cocoa (for a sweeter finish, mix with a little caster sugar). Strew the top with blueberries or raspberries if liked, and serve.