Beat the butter with the sugar until frothy, stir in each egg individually and keep beating. Add the lemon juice, flour and baking powder and stir everything together.
Spread 1/4 of the dough thinly on a baking sheet. Bake in the preheated oven for approx. 4 - 5 minutes. Be careful not to let the floor get too dark. Proceed in this way until the batter is used up. Let all bottoms cool, cut off the edges and save.
For the filling, whip the cream until stiff and stir in the condensed milk.
Lay the first floor on a countertop and spread some of the cream. Put the 2nd floor on top, spread the cream on it again and continue so until all floors are coated. Finish with the cream.
Crumble the cut edges from the bases and spread them on the cake.
It is best to prepare the cake a day in advance, then it tastes better. The cake is delicious, but also very powerful.