Heat 450 ml milk, salt and a packet of vanilla sugar. Caramelise the sugar in a wide pot until light brown. Deglaze with 5 tablespoons of boiling water, then add the hot milk.
Mix the remaining milk, egg yolk and starch. Stir into the boiling caramel milk and bring to the boil again briefly. Rinse pudding portion bowls (150 ml content) with cold water and pour in the Flummeri immediately.
Let it cool down. In the meantime, lightly whip the whipped cream, add the remaining vanilla sugar, stir and fold in the egg liqueur. Turn the flummery over onto a dessert plate, arrange with the advocaat cream, decorate with pistachios and, if desired, with some lemon balm.