Heat olive oil in a large pot or Dutch oven over medium heat. Add the minced garlic and sauté for 1 minute until fragrant, being careful not to let it brown or burn.

Pour in the chicken or vegetable broth and bring it to a rolling boil over medium-high heat.

Add the pastina to the boiling broth. Stir well and cook according to package directions (typically 5-7 minutes) until the pastina is al dente.

While the pastina is cooking, whisk the egg in a small bowl until smooth. Slowly temper the egg by adding a ladleful of the hot broth from the pot into the egg mixture, whisking continuously. This crucial step prevents the egg from scrambling when added to the soup.

Once the pastina is cooked, remove the pot from the heat. Slowly pour the tempered egg mixture into the hot soup in a thin stream, stirring constantly to create delicate, silky strands throughout the soup.

Stir in the grated Parmesan cheese and chopped fresh parsley. Season with salt and freshly ground black pepper to taste. Ladle the hot soup into bowls and serve immediately, offering extra Parmesan cheese for garnish if desired.