Enchantress cake with custard soaked in syrup

Mix eggs at room temperature with a mixer. Add sugar, in three steps. Beat for about 15-20 minutes. In conclusion, add salt. Beat to a state where the trace of the mass flowing from the mixer does not immediately dissolve on the surface of the total mass.
Then add the sifted flour in parts and gently mix into the whipped mass.
Cover the bottom of the baking dish with baking paper. Put the dough into the mold. It is not necessary to lubricate the mold with oil.
Bake in a preheated 180 °C oven for 30-40 minutes. Do not open the oven for the first 20 minutes.
Check the readiness of the biscuit with a wooden stick. Cool the sponge cake in the mold for 15 minutes. Then cut it out of the mold with a knife, release the bottom of the biscuit from the paper. Wrap the cooled biscuit in plastic wrap and put it in a cool place for at least 5 hours (so that it does not crumble when cut).
Prepare custard. In a saucepan, mix sugar, vanilla sugar, salt, flour and egg. Add half of the milk from the total norm. Stir with a whisk. Heat the mixture on the stove, stirring continuously. Add the remaining milk. Bring to a boil. The mixture should thicken. Add butter at room temperature. Mix it. Cover the cream with cling film in contact and place in a cool place.
For the syrup, combine water and sugar, put on the stove, bring to a boil. Cook for 1-2 minutes on low heat. Cool it down. Mix with cognac (optional).
Cut the biscuit lengthwise, into two parts. Soak both parts with syrup.
Put the cream on one part of the biscuit, cover the second part on top.
For the glaze, melt the chocolate and butter in a water bath.
In conclusion, decorate the cake with chocolate icing. Put it in the refrigerator for at least 3 hours.