Add olive oil to a hot pan and saute the onions until transparent. Add salt and pepper to taste.
Next, add the ground Italian sausage to the pan with the onions and cook until no longer pink.
In a separate bowl, mix the eggs, parsley, parmesan cheese, salt and pepper to taste. Mix the eggs into the sausage and onions so it is distributed well.
Add some pearl mozzarella balls to the top, then sprinkle on some more parmesan cheese.
Bake in the oven for 3-4 minutes, or when the eggs are set to your preffered level.