For the vanilla sauce, mix cornflour and 1 tablespoon of milk. Put 1/8 litre milk, 50 g cream, vanilla sugar and 1 tablespoon sugar in a pot and bring to the boil. Add starch while stirring and bring to the boil again.
Peel and quarter apples, except one half, cut out the core and cut them into pieces. Quarter the remaining half of the apple, remove the core. Cut the fruit flesh into slices. Sprinkle with lemon juice.
Mix flour, salt and the remaining milk and cream with the whisks of the hand mixer. Separate the eggs and add the egg yolks one after the other to the flour mixture. Mix well together. Beat the egg white and the remaining sugar with the whisks of the hand mixer until stiff and carefully fold into the egg-flour mixture.
Dab apple pieces dry and fold into the dough. Heat oil in a pan and bake the dough in it in portions. Fry on one side for 2-3 minutes on medium heat until golden brown, turn and tear apart with two forks.
Fry until golden brown all around. Remove and keep warm. Sauté apple slices in cooking fat on both sides for 1-2 minutes and arrange on a plate together with the Kaiserschmarrn. Dust with icing sugar and serve decorated with mint leaves as desired.
Serve with vanilla sauce.