Pesto keeps in the refrigerator for up to a week. Pesto may be frozen. Blend cheeses together. Add green onions, spinach, garlic, salt and pepper. Mix in eggs.
Stuff shells with filling.
Layer in baking pan. Cover with marinara sauce and sprinkle with additional parmesan. May be frozen for 30 days or refrigerated for two days. Bake at 350 degrees for 30 minutes until warm. Plan two shells for appetizer portion or three shells for entree portion.