Bring the chicken broth to a boil in a medium saucepan.
Add the pastina and cook according to package instructions, stirring occasionally.
Once the pastina is cooked, reduce heat to low and stir in the butter.
In a separate bowl, beat the egg with the Parmesan cheese.
Slowly drizzle the egg mixture into the soup while stirring to create egg ribbons.
Season with salt and pepper to taste.
Serve hot, garnished with fresh parsley if desired.