Peel the onion and cut it into small pieces.
Grate the two cheeses and have them ready on a plate.
Mix eggs, flour, water and salt to make a tough, firm dough. Boil about 5l of water, season heartily with salt, maybe add a dash of oil. Pour the dough through a spaetzle slicer into the boiling water. Bring to a boil, and as soon as the spätzle have risen, skim off.
Layer spatulas layer by layerin a baking dish. Sprinkle cheese over each layer. Finish with sparrows. Finally, pour a ladle of salted water or beef broth over the top. Cover and keep warm on steam.
Melt butter in a frying pan. Fry the finely chopped onion until golden brown, pour over the sparrows together with the butter. Serve sprinkled with fresh black pepper and chopped chives.
Our tip: Always use fresh chives if possible!