The calculation in the recipe is for a 22cm (8.66 inch) cake.
- Pour the flour with cocoa into a mixer bowl, and combine.
- Add the softened butter (cut into cubes) to the flour. Make chocolate crumbs using a mixer (or by hand).
- In a bowl, combine the water, egg, vinegar and salt.
- Turn on the mixer at a low speed (or do it in a bowl or on the table with your hands), and add the liquid mass to the chocolate crumbs in parts. Knead a soft, tender, slightly sticky dough.
- Put the dough on a plate sprinkled with flour, cover with film, and refrigerate for 1-2 hours until cool.
- You better roll out the dough on floured parchment, between 2 sheets of parchment. Then carefully remove the top parchment, cut out a circle of the desired diameter (don't remove the edges, bake with them, they will go to crumbs). Pierce the crust with a fork. Immediately after rolling out and cutting out the circle, do not bake! Let it lie on the table for a couple of minutes.
- Bake the cake layers at 392F (200C) for 10 minutes.
- Bring the milk and sugar to a boil.
- Mix the eggs with flour. Pour a little hot milk into a bowl with eggs, and mix.
- Pour the whole mixture into milk, stirring constantly; bring to a boil, and cool at room temperature.
- Whip the softened butter with condensed milk, add the custard in parts, and whip everything together.
- Assemble the cake in a ring, lining the sides with acetate or cling film.
- Alternate the cake layers and the cream. Place the assembled cake in the fridge overnight.
- Remove the ring and film, sprinkle the top and the sides of the cake with crumbs (make crumbs from scraps, chopping them with your hands).