Peel and finely dice the onion and fry it with 1 tablespoon of butter in a small pot until transparent. Cut the crust off the toast. Grate the Parmesan finely. Cut bread and mountain cheese into fine cubes and put them in a bowl with Parmesan cheese.
Whisk eggs and milk and add to the bowl with the steamed onions and flour. Season with salt and pepper and knead everything into a smooth dough. Bring plenty of salt water to the boil in a large pot.
Dip 2 tablespoons into lukewarm water, use it to make cams on the dough and put them into the boiling water. Cook the noodles for 5-6 minutes until they float in the pot. Take them out and let them drain.
Wash and halve the tomatoes. Clean spring onions, cut off green ends 6-10 cm, wash and halve lengthwise. Heat 1 tablespoon butter in a coated pan. In the meantime cut the spring onions in half crosswise.
Add spring onions and cherry tomatoes to the pan. Fry for approx. 5 minutes over a low heat, stirring gently from time to time. Season with salt and pepper. Heat 1 tablespoon of butter in another large frying pan.
Fry the Kasnocken for about 3 minutes while turning them golden brown, season with salt and pepper. Arrange vegetables and Kasnocken on preheated plates.