1. In a large saucepan, bring the broth to a boil. 2. Add the orzo, rice, or pastina and cook until tender but still al dente, about 7 minutes (20, if using rice). Season with the salt and pepper and reduce heat to low; simmer. 3. Meanwhile, in a medium bowl, whisk together the eggs and lemon juice until smooth. 4. Ladle about 1 cup of the hot broth into the egg-and-lemon mixture, then whisk to combine. 5. Add the mixture back to the simmering saucepan. Stir just until the soup becomes opaque and thickens as the eggs cook, 1 to 2 minutes. Add more salt and pepper, if desired, and serve.