• The cake has to be made at least two days, preferably three days in advance.

Cake layers:

• Cream ingredients: Place the soft butter, eggs, smetana or sour cream, sugar, and vanilla sugar or extract in the bowl of the stand mixer. Mix until creamy.

  1 cup unsalted butter + 2 large eggs + ⅓ cup smetana/sour cream + ¾ cup granulated sugar + 2 tablespoons vanilla sugar
• Mix dry ingredients: In another bowl, mix the flour and the baking powder. Add them to the rest of the ingredients and mix well.

  4⅓ cup all-purpose flour + 3 teaspoons baking powder
• Refrigerate dough: Turn the mixture on the lightly floured working surface and knead shortly to obtain a smooth dough. Wrap the dough in cling foil and refrigerate for one hour.
• Preheat the oven to 400°F/200°C.
• Divide the dough into four equal parts. Cut four large pieces of baking paper. Flour the rolling pin.
• Roll: Flatten the first piece of dough on one piece of parchment paper to get a rough rectangle, and then roll it to a rectangle of about 9x12 inches/ 23x30 cm. It works better if you have a small rolling pin, which you can hold in one hand while holding the baking paper with the other hand. If you only have a regular-sized rolling pin, maybe someone can hold the baking paper for you, or you can fix it down with tape.
• Trim edges: Gently press the dough's edges with a butter knife or your fingers to even them out and keep them from thinning, preventing them from drying out during baking. The edges don’t need to be perfect - you can trim them neatly after the cake has rested for two or three days.
• Bake first dough layer: Carefully place the dough on the baking sheet and bake in the preheated oven for about 10 minutes or until the edges of the dough rectangle start to get brownish. Remove from the oven and let cool completely.
• Bake remaining layers: While the first cake layer is in the oven, roll the second one and so on until all four cake layers are baked.

Filling:

• Layer cake: When the cake layers are cool, layer them with jam. Stir the jam well before spreading it on the cake layers.
• Assemble the cake: Choose the nicest cake layer and set it aside to use it as the top layer. The first layer should be smeared with plum jam, the second with apricot jam, and the third one with plum jam again. Place the last cake layer on top and press gently.

  14 oz plum jam + 7 oz apricot jam

Glaze:

• Mix the egg yolks, icing sugar, lemon juice, and vanilla extract in a small bowl.

  4 egg yolks + 1 cup powdered sugar + 1 tablespoon lemon juice + ½ teaspoon vanilla extract
• Prepare for glazing the cake: Place the layered cake on a large baking tray or a wooden board. If using a wooden board, set it inside a baking tray to catch any glaze that drips down the sides.
• Start spreading the glaze on top. If it's too runny, add more powdered sugar until it reaches the right consistency. The amount needed depends on the egg yolk size.
• Top the cake with colorful sprinkles. The cake can also be topped with roasted and chopped nuts of any kind or with chocolate sprinkles. Leave the cake to rest on the counter until the glaze is dry.

  5.5-7 oz colorful sprinkles

Store:

• Wrap the entire cake tightly in plastic wrap, including the wooden board, baking tray, or casserole dish. I use a double layer to ensure there are no gaps or openings.
• Leave the cake to rest for 2 or 3 days in a cool place. It doesn't have to be the fridge, but make sure is cool. I always keep it in the cellar.
• Cut the edges of the cake straight. Cut the cake into small squares.
• Keep in airtight cookie tins with parchment paper between the layers of cake.