For the layers, first mix the baking soda with the yogurt. Beat the eggs with the sugar until white, then add the yogurt and all the other ingredients for the layers. Bake 3 separate layers in an oven dish, covered with baking paper.
Optionally one can color one of the layers with a spoon of cocoa. Prepare a sugar syrup from 2 cups water and 6 tsp sugar, boil them on the stove.
For the cream, heat the milk with the sugar. In a thin trickle, pour in the pre-beaten eggs and flour. Stir until the cream thickens and then add the vanilla, lemon zest and 2 tablespoons butter.
All the ingredients for the cake should be well cooled. Place the first layer on a platter, syrup it, add cream and repeat this process with the remaining layers.
Coat the entire cake with cream and decorate it with walnuts. Put the homemade cake with vanilla cream in the refrigerator for several hours before serving.