Heat the oil in a Dutch oven or stockpot. Cook the onion and chopped spinach for 5 minutes or so, until softened and wilted. Add the broth and bring to a simmer. Simmer 30 minutes, then cream it all together with an immersion blender. Add cooked rice here if you want to make it a more filling soup.

Blend the eggs, cheese, salt, pepper, and nutmeg in a bowl. Pour into the soup, stirring, and simmer another 8-10 minutes.