Base: The biscuits are ground in a blender or nice are broken into small pieces, mixed with melted butter, sugar and gently broken egg white . Bottom round baking tin with a diameter of 24 cm is stood with baking paper. The mixture was partitioned by the bottom and sides by pressing well. Leveled with a spoon. Bake in a preheated oven at 180C ° for 10 minutes, then cooled. Cream: Cream the feta cheese, sour cream and sugar is broken, add egg yolk and vanilla, stir briefly. Half a cup of the mixture aside. May instead Bulgarian cream cheese to use mascarpone or cream cheese Philadelphia. Dark chocolate is melted in a water bath and mixed with the allocated portion of the cream. White cream is placed on the cooled base leveled well. Chocolate mixture is placed in a posh and make marks on a white cream and lightly deep. The mold is placed in a tray, pouring water (2 cm) and baked cheesecake in a heated oven at 150-180C degrees (no fan) for 50 minutes. Then the oven is switched off, the door opened slightly and leave the cheesecake inside for 30-40 minutes. Cool before serving a minimum of 4 hours in the refrigerator. Thus prepared cheesecake it is not very sweet, slightly sour but very pleasant flavor. I hope the recipe to please.