Beat the egg whites with the sugar and salt and put aside. Put milk, egg yolks, sugar, cornstarch and possibly vanilla in a large saucepan and stir.
Bring to the boil while stirring. Cook for another 2 minutes, then place in an ovenproof dish. If you want, you can line the mold with biscuits beforehand. Spread the egg whites on top.
Place the tin in the oven preheated to approx. 175 ° C and bake until the meringue is slightly brown. Maybe sprinkle a little caramel on top. Chill before serving.