Remove the butter and margarine from the refrigerator in advance so that they are soft before cooking. Clean the walnuts.
Place softened margarine, granulated sugar, sour cream in a deep bowl, stir until smooth. Add flour to the resulting mass and knead the dough. Place the dough in the refrigerator for 4 hours
While the dough is cooling, prepare the cream. In a deep bowl, stir boiled condensed milk and butter until smooth.
Remove the chilled dough from the refrigerator. Grind or mince to form uneven pieces of dough. Preheat oven to 200℃. Bake the dough for 10 minutes until golden brown. Once the dough is baked, take it out and let it cool. Grind the cooled dough by hand or with a rolling pin into small pieces.
Assemble the cake. Grind the walnuts with a blender or rolling pin. Place pieces of dough, cream into a deep bowl, add chopped walnuts and mix. Carefully place the resulting mass on a plate, forming it into a slide.
Decorate your homemade cake with poppy seeds or chocolate by carefully sprinkling the top of the cake.