Boil the milk with the vanilla sugar and 5 1/4 oz of caster sugar. Whisk the egg whites, as soon as they have started to set, gradually add the remaining sugar and continue to whisk until very firm. Scoop the egg whites with a large spoon, place them 4 at a time in the gently simmering milk and poach for 2 to 3 minutes, turning them over once. When poached, drain them on a cloth. Keep chilled. Beat the egg yolks. Strain the milk in a sieve and bring to a boil, adding a little more milk if necessary, to have 1 quart. Make a custard, leave to cool. Mound the egg whites in a dome in the serving bowl and keep refrigerated until ready to serve. Fill the base of the serving bowl with some of the custard and serve the rest in a sauceboat. This is a stylish way of presenting snow eggs, allowing larger quantities to be presented for a festive meal.
