Crush biscuits in a bowl and pour melted butter over them. Mix well and press into a 23cm round cake tin or tin foil tray. Pop in the preheated oven for about 10 minutes. Allow to cool.
In a large bowl, beat together the cottage cheese, dried milk and caster sugar. Stir in the lemon zest.
In a saucepan of water, put a heatproof bowl or jug. Add 300ml water, the juice of both lemons and the gelatine. Stir over low heat until it is all dissolved. Slowly stir into cheesecake mixture and mix completely.
Slowly pour the liquid over the cooled base and place in the fridge to set, about 3 hours.
If using a tinfoil tin, decorate with fresh fruit and cream, or tinned pie filling.