Beat flour, eggs, water and 2 g salt into a thick elastic batter. Rest for 15 minutes.
Slice onions thinly and cook in butter over medium-low heat for 20 minutes until golden, stirring often.
Bring a large pan of water to a gentle boil. Press batter through a spätzle maker or scrape thin strips from a wet board; lift out after they float and cook for 1 minute more.
Layer hot spätzle with grated cheese in a warm pan. Cover over low heat for 3 minutes to melt, then top with onions, parsley, remaining salt and pepper.
Choose vegetarian-rennet cheese. Batter thickness varies with flour; add a little water only if too stiff for your spätzle tool.
Käsespätzle
Allergens and ingredient checks
Listed allergens: eggs, gluten, milk. Check actual packaging and cross-contact information. Nutrition is estimated from ingredient weights; recipe suitability depends on the specified products.