This soup is a riff on the Greek avgolemono: a delicious concoction of beaten eggs and lemon juice, whisked into broth and cooked just enough to thicken. We borrowed the egg and lemon motif, and we also added spinach and orzo.
This soup has one other curious feature. It really is a pasta and a soup in one -- a two'fer.
See, when you reheat the leftovers, the orzo will thicken even more and the egg will expand so much that you're left with a bowl of creamy, lemony, spinach pasta. Which is not such a bad thing, really.
Of course, what's really happening is the eggs are curdling when reheated. This is unavoidable in a soup like this, and we really didn't mind. In fact, the thick, creamy orzo we ate on the second night was delicious and reminiscent of risotto.
But a fair warning: if you just want soup, eat it all the first night, or whisk the eggs and lemon juice into just half a batch, and repeat on the next night.
Spinach and Lemon Soup with Orzo
2 tablespoons olive oil 4 garlic cloves, smashed or minced 1 large onion 1 teaspoon red pepper flakes (or more, depending on your taste) 1 package frozen spinach, thawed and drained of excess water 1 1/2 cups orzo 8 cups chicken or vegetable broth 4 eggs Juice of 3 lemons Fresh parsley, chopped (to serve) Fresh-grated Parmesan (to serve)
Heat the olive oil in a large heavy pot or Dutch oven. Cook the garlic and onion over medium heat until fragrant and slightly translucent. Turn the heat to medium high and add the red pepper flakes, spinach, and orzo. Cook for about a minute, then add the broth.
Bring to a light simmer, then turn the heat down and simmer for about 15 minutes, or until the orzo is just barely tender. Take the soup off the heat and let it cool down for a moment or two.
Whisk eggs vigorously in a largish bowl, then whisk in the lemon juice. Whisk for a couple minutes; the mixture should be thick, pale yellow, and creamy. Add a small ladleful of the soup broth to the eggs and whisk vigorously. (If you want to be really sure not to curdle the eggs, take a ladle of soup and cool it a bit before tempering the eggs.) Whisk in two more ladles of soup broth, whisking each well and letting them cool.
Add the egg mixture to the soup pot, whisking very well. Return to very low heat, stirring the whole time. Cook carefully over low heat until the soup has thickened slightly. Serve immediately, garnished with parsley and Parmesan if desired.