n Ingredients should be at the room temperature. Sift the flour into the bowl, add chopped butter, egg yolks and white,  sour cream and icing sugar. Knead all together. Put the dough into fridge for at least 1 hour.nn Lined baking pan with baking paper. Preheat the oven to 375 degrees F (190C).nn Roll the cake (use potato flour if dough is sticky), using medium size plate punched a circles , which then divide to 8 parts (created 8 triangles). In the wider part of each triangle put a bit of jam and roll up – starting from the wider side to narrow (picture on website).nn Put cookies on the baking paper, in small space between. Bake about 15 minutes (until nicely golden brown). After cooling sprinkle with powdered sugar.n