Preheat the oven to 350 degrees.
Slice two medium zucchini in half and scoop out the insides with an ice cream scoop.
In an sauté pan on the stove, add extra virgin olive oil and heat. Then add onions and cook for 3 minutes or until they are translucent. Then add in the garlic and cook another 2 minutes.
Add in the zucchini and cook for 3 minutes. Remove everything from the pan to a large, heat safe bowl.
Wipe out the pan and add the Italian Sausage and brown. Then drain the sausage well.
Combine the sausage with the zucchini mix and add in the parmesan cheese, basil and egg. Mix well. *If you want breadcrumbs, add them now.
Spoon the mixture into the zucchini boats. Drain the spoonfuls before adding. Leave any extra water/grease at the bottom of the bowl.
Bake for 20-25 minutes. You'll know it's done when the tops of the sausage are starting to brown slightly.
Top with your favorite marinara sauce or my homemade Roma Tomato Sauce. Top with additional cheese and basil. Salt and pepper to taste.