Beat butter with sugar and eggs. mix flour, starch and baking powder.

Put the dough into the split mold 23 cm in diameter, lined with paper and flatten. Bake 30 min. Remove and allow to cool.

Soak gelatine in 2 tbsp water and dissolve. Mix sour cream, sugar, cream (I used 30%, and can be less %), vanilla sugar, zest and lemon juice. Mix with the gelatin. Cool slightly cream. Put the cake in a detachable form, to pave the roll-shaped paper, spread the cake cream and levelling. Put in the fridge for about 3 hours (not the freezer!)

Cherry juice can be obtained in three ways. First - using a juicer, the second punch seedless cherries in a blender, then RUB through a sieve, and the third to fill the pitted cherries with sugar for a few hours and carefully drain the separated juice. I have used the third option. To do this, took 500 gr. cherries, removed seeds, filled with sugar, a few took a spoon of the berries left for a few hours, drained the juice, turned out 150 ml, refilled to a full Cup of boiled water.

Got this transparent juice. In any case, in the juice add sugar to taste.

Mix the starch with 4 tbsp of cherry juice. Boil the remaining juice, remove from heat, pour the starch into it, stir, put half of the berries and put on low heat for 1 minute, stirring with a spoon. Remove from heat and add remaining berries. Give mass to cool.

Put on the cream a lot and chill for 1 hour. Decorate the cake with fresh berries, mint and serve.