For the whole wheat spinach spaetzle dough, mix flour, eggs, olive oil, defrosted spinach and skim milk to a viscous dough.
Season with salt, nutmeg and garlic, let rest.
In the meantime, finely chop onion and roast in olive oil.
Gently fold the spaetzle dough into boiling salted water with a spaetzle slicer.
Let it boil for about 10 minutes, strain and rinse with cold water.
Mix the spaetzle with the roasted onion.
For the cheese sauce, stir flour in a little cold milk until smooth.
Bring remaining liquid to a boil.
Stir cheese wedges and flour-milk mixture into boiling liquid and cook for a few minutes, stirring constantly.
Season to taste with spices.
Arrange wholemeal spinach spaetzle with cheese sauce on plates.