Preheat oven to 400° Fahrenheit.
Using a spoon, scoop out and remove the seeds and a little bit of the flesh from each zucchini half.
Sprinkle zucchini with salt and black pepper, then place inside a large baking dish and set aside.
Heat avocado oil in a large skillet over medium heat, then add in the Italian sausage and cook until no longer pink. Break up the meat as it cooks, should take about 5 minutes.
Add marinara sauce to the skillet, reduce heat to low and simmer sausage in sauce for 2-3 minutes.
Spoon the sauce mixture into the cavity of each zucchini half, then evenly sprinkle with Italian seasoning. Bake for 20-25 minutes or until sauce is bubbly and zucchini is tender. Serve warm with parmesan cheese and fresh basil.