Grease the baking tin with butter. If you have a springform tin, you can line the base with baking paper.
Beat eggs, sugar, vanilla and salt for approx. 10 minutes until light and fluffy.
Add sour cream and sweetened condensed milk and mix briefly to form a homogeneous mixture.
Mix 160 g flour with baking soda, sieve it into the egg sugar mixture and fold it in to form a thick batter.
Divide the batter into two equal portions.
Sieve 30 g of flour into one of the batter portions, fold it in and pour the batter into the baking tin.
Bake the light cake base in a preheated oven at 356 °F (180 °C) for approx. 15 minutes.
In the meantime, sieve cocoa powder into the second portion of batter and fold it in.
Carefully remove the light cake base from the baking tin immediately after baking, grease the baking tin again and pour the chocolate batter into the tin.
Bake the dark cake base directly after the light cake base again at 356 °F (180 °C) for approx. 15 minutes.
Leave the light and dark cake bases to cool and then cut them lengthwise into two thinner cake bases each, so that you now have two light and two dark cake bases.
Soak the four cake bases with peach water.