Adding eggs to soup is among the easiest ways to deliver richness, body, and flavor. It’s the simplest way to add protein too.
In Egg Drop Soup, Many Ways (page 141), the technique is to “scramble” beaten eggs into bubbling stock; the result is thin, tender wisps of egg throughout the soup. This is a technique you can do with almost any soup.
If you don’t want those obvious egg strands, you must temper the eggs — mix them with a little hot broth before adding to the soup. As the eggs warm, the soup will thicken naturally, as long as you’re careful not to boil the soup and curdle the eggs. This is another technique you can use elsewhere.
To poach eggs in soup, gently slip whole eggs into the hot soup, again being careful not to let the liquid boil vigorously. This is a technique I love; you’ll see it in the variation Poached Egg Soup (page 142), but again, it’s useful in many other instances.
Finally, you can top soup with already cooked eggs, whether they’re fried, scrambled, poached, hard-boiled, whatever. See the list on page 142 for the most basic ideas. Or try the Egg “Noodle” Soup with Mushrooms (page 143) for something a little fancier.