To make this 20-minute immunity-boosting pastina, start by heating a large pot over medium heat. Add the butter and let it melt completely.
Once the butter is melted, add the chopped carrots, celery, and onion. Sauté for about 5 minutes, stirring occasionally, until the vegetables begin to soften. Stir in the mashed garlic and cook for 1 more minute, just until fragrant.
Add the pastina, chicken bone broth, kosher salt, and turmeric. Stir everything together, then let the soup simmer for 7–9 minutes, or until the pastina is fully cooked. Turn the heat off once the pasta is cooked.
While the soup is simmering, make the egg-cheese mixture. In a medium bowl, whisk together the eggs and grated Parmigiano Reggiano until a thick paste forms.
Carefully ladle about 1 cup of hot broth into the egg-cheese paste, whisking continuously as you pour to temper the eggs and prevent scrambling.
Slowly pour the mixture back into the pot. Add the fresh lemon juice and stir again.
Ladle the soup into bowls and garnish with chopped parsley and a drizzle of chili crisp if you like heat. Serve hot and enjoy!