Blend the biscuits in a blender and pour them into the bottom of a tray. Melt the butter and pour it evenly over the crumbs. Stir to distribute the butter along the crumbs, pour in 3 tbsp milk and stir again. Press the crumbs into an even layer along the bottom of the tray.
Soak the gelatin in the amount of water listed on the packets. Once swollen, carefully melt it on the stove and leave to cool. Meanwhile, beat the cottage cheese, sugar, sour cream, milk. Pour in 2-3 tbsp of the jam into the milky filling and stir. Add the gelatin and beat again.
Pour the mixture over the layer, put it in the fridge for a few hours to harden.
Dissolve the gelatin for the topping in water, melt it and mix it with the remaining cranberry jam. Once the mixture cools, pour it over the milky layer and return to the fridge once again to harden.