Beat eggs with sugar until white. In a bowl mix the walnuts, flour, vanilla and baking powder. Beat eggs, add the dry ingredients and gently stir. Pour the dough in a baking dish - 26-28 cm in diameter, covered with baking paper. Bake the base in a preheated 170C oven for about 25-30 minutes. For the cream into a bowl, beat the sour cream with the chocolate spread, them add the cream and gelatin, previously dissolved in 100 ml water in a water bath. Mix with mixer until homogeneous. Cut the base in the middle, spread with cream, cover with second base and again smear with cream.