A day before baking, age the egg whites: leave them at room temperature for 24 hours, until small bubbles appear.

Draw two circles, 23 and 20 cm in diameter, on parchment paper. Preheat the oven to 150°C.

Toast the hazelnuts, peel them, and chop coarsely with a knife. Combine the nuts with the sugar (185 g) and flour.

Whip the egg whites, gradually adding the remaining 50 g of sugar, until stiff, firm peaks form.

Fold in the dry mixture quickly and gently, then spread the batter over the two prepared circles.

Bake for exactly 2 hours at 150°C. The finished layers should be cream-colored, dry and crisp. Leave them out overnight in a dry room.

In the morning, remove the parchment, place the smaller layer on the larger one, and trim it to size. Save the trimmings for crumbs.

Warm the milk. In a bowl, mix the sugar with the egg, pour in the warm milk, mix, and return to the saucepan.

Stirring constantly, bring the syrup to a light simmer and a boil, remove from heat, strain, cover with plastic wrap pressed onto the surface, and cool.

Whip the soft butter, gradually add the cooled syrup, and whip into a fluffy cream, flavoring with cognac at the end.

Set aside most of the cream and mix cocoa into it - you'll end up with two creams, chocolate and plain.

Spread the plain cream over the first layer, saving a little for decoration. Top with the second layer and spread with chocolate cream, including the sides.

Coat the sides with the crumbs from the trimmings, pipe a border and little flowers with the remaining cream, and decorate with nuts and jelly candy if you like.

Chill the cake for 3-5 hours.