Beat the eggs and sugar together until the mixture becomes pale and thick. Add the dulce de leche and beat again. Then mix in the sour cream
In a separate bowl, sift together the flour, cocoa, and baking soda. Combine the dry ingredients with the egg mixture using a hand whisk.
Line the baking pan with parchment paper, grease with butter, and pour in the batter. Bake in a preheated oven at 180 degrees Celsius for about 25 minutes. Check with a wooden skewer; if it comes out dry, the cake is ready.
Let the sponge cake cool completely, then cut it into two or three layers.
To ensure the cream turns out well, the butter and dulce de leche must be at room temperature. I made the cream with a hand whisk, and it turned out great. First, beat the butter a little, then gradually add the dulce de leche, and finally the cocoa powder. The delicious cream is ready.
Spread the cream on the bottom layer of the sponge cake, then place the second layer on top. Put the cake in the refrigerator.
While the cake is chilling, prepare the chocolate glaze. In a small saucepan, combine the butter, sugar, cocoa, and milk. Heat over low heat, stirring constantly until it becomes a smooth mixture. Remove from heat just before it starts to boil, let it cool slightly, then pour it over the cake.
The delicious "Prague" cake is ready. Bon Appetit!