In a deep bowl, mix the flour and salt. Add the cold butter and rub it into the flour to get a sand-like mixture. Add the lemon zest, eggs and vanilla extract. Knead the dough and leave it to cool in the refrigerator for about 20-30 minutes. Roll out half of the dough and place the crust in a round pan with a mechanism, forming edges about 5 cm high. Leave in the refrigerator to cool. In a deep bowl, mix together the cream cheese and sour cream. Add the sugar, starch, eggs, vanilla and mix well. Finally add the aronia (chokeberry) and transfer the cream-cheese and aronia (chokeberry) mixture to the dough. Crush the other half of the dough on the filling. Bake in a preheated oven at 170 degrees for about 60-70 minutes.