This biscuit cake is unbelievably delicious. I was surprised myself.
Clean, peel and cut the apples into small cubes of roughly the same size.
Put the water in a pot, place the apples, sugar, vanilla and bring to a boil. Boil until the apples soften - it took 15 min. in my case.
Take off the stove and pour the sour cream into the hot mixture, stir. The mixture isn't going to look aesthetically pleasing but don't worry about that.
Take a rectangular or round form of about 9″ (22 cm). Arrange a layer of biscuits on the bottom, fill the empty gaps with biscuit pieces so that the whole bottom is covered.
Finish off with a layer of apple mixture, cool at room temperature and then put the whole cake in the fridge.
Decorate if desired with chocolate or nuts. For the best taste possible, leave it for 24 hours in the fridge to cool.
This recipe is adapted from Albena Todorova and Morena.