For the spinach spaetzle, first whisk the flour with the eggs and salt until a uniform batter is formed. Fold in the spinach. The dough must be stirred until it bubbles.
In a large saucepan, bring plenty of salted water to a boil.
Scrape the spaetzle dough into the water in batches. When the spaetzle float to the top of the water, they are done.
Remove the spinach spaetzle and drain. Heat the butter and pour over the spaetzle.
Spinach spaetzle can be served as a main dish or as a side dish.