Blitz the biscuits in a food processor or crush finely in a plastic bag using a rolling pin. Stir in the butter. Spread the mixture over the base of the prepared cake tin, press down well with the back of a spoon or the base of a glass, refrigerate.
Cream cheese mixture
Puree the beetroot with the sugar, pass through a sieve, set aside. Mix the cream cheese and quark. Stir in the eggs and all the other ingredients up to and including the flour. Spread the raspberries on top of the biscuit base, spoon the cream cheese mixture over the raspberries. Spread the beetroot puree on top, create a marble effect using a fork.
Approx. 60 mins. in the lower half of an oven preheated to 180°C. When baked, turn the oven off and allow the cheesecake to cool in the oven for approx. 15 mins. with the oven door slightly open. Remove from the oven, cool on a cooling rack, remove the tin frame.