Beat the egg whites to foam, add the sugar in lots. Put them in a water bath and beat continuously until they become very thick and shiny, while the sugar becomes completely absorbed.
In a form covered with baking paper and oiled, pour on the white mixture using a pastry bag, then the yellow one. The result is 2 cake layers.
Bake at 356°F (180 °C) about 15-20 min. Let them cool fully.
Heat the milk with the sugar. Add the vanilla.
Beat the yolks with a whisk and add the starch, dissolved in a little water. Stir.
Once the milk reaches boiling point, add the yolks with the starch, and while stirring nonstop boil a thick cream. Cool completely.
Assembling the cake
Smear the first cake layer with jam, distribute cream on top and cover with the 2nd layer. Distribute cream again.
Sprinkle with powdered sugar if desired.