Makes about 15 servings.
Bring 18 cups of chicken stock to a boil. Add 2 cups of dried Arborio rice, reduce to a simmer and cook, uncovered, for 20 minutes or as long as the package says the rice needs to be cooked.
Meanwhile, in a large bowl, beat 5 eggs, 1 tsp. freshly ground black pepper, and 1 cup of lemon juice until well combined.
When the rice is almost done, ladle about 5 or 6 cups of the egg and lemon mixture while whisking vigorously, until well combined. Then whisk the mixture into the pot and simmer for 5 more minutes. Add more lemon juice and ground black pepper to taste.
The soup can be served immediately; however, after refrigerating overnight, the rice and stock will become more uniformly combined. If you're planning on serving this soup to a large party, I recommend making it the day before and adding a little water just before reheating and serving to get the consistency just right.