Cut the vanilla pod in half lengthwise. Scrape out the pulp. Pour plums into a sieve. Collect the juice in a pot. Simmer at low heat with 1 teaspoon sugar, cinnamon, half of the vanilla pulp and the vanilla pod for about 15 minutes.
In the meantime, separate the eggs. Chill the egg white. Whisk the egg yolks, remaining vanilla pulp and 60 g sugar with the whisk of the hand mixer until white-creamy. Add milk while stirring. Stir in flour, allow to swell for approx. 10 minutes
Mix orange juice with starch until smooth and stir into the hot plum juice. Add the plums and simmer for about 3 minutes, stirring occasionally. Remove from the heat and allow to cool
Beat the egg whites until very stiff and allow 40 g of sugar to trickle in. Fold the beaten egg white into the dough. Heat 2 tbsp. butter in a large pan. Add half of the dough and bake at medium heat from the bottom side until golden brown. Turn with the help of a large pallet, allow to set briefly. Then pluck the dough into pieces with 2 forks and dust with 1 tsp. icing sugar. Fry the dough pieces all around until golden brown. Keep warm in a preheated oven (50 °C). Do the same with the remaining dough, butter and 1 teaspoon icing sugar.
Arrange Kaiserschmarrn with plum sauce on plates and dust with 1 tablespoon icing sugar each