Preheat oven to 375 degrees F. Line a baking sheet with parchment paper.
Using a spoon, scoop the flesh from the center of each zucchini half, leaving a 1/4-inch border. Place the zucchini on the prepared baking sheet.
In a large nonstick skillet, heat the olive oil over medium-high heat. Add the Italian sausage and cook, stirring often, until browned, about 5 minutes.
Stir in the marinara sauce, mozzarella cheese, Parmesan cheese, and Italian seasoning. Cook, stirring often, until the cheese is melted and the mixture is heated through, about 2 minutes.
Spoon the sausage mixture into the zucchini boats. Sprinkle with salt and pepper, to taste.
Bake in preheated oven until the zucchini is tender and the cheese is melted and bubbly, about 15 minutes.
Serve warm.
Interesting Facts
Zucchini is a member of the squash family.
Zucchini is low in calories, fat, and cholesterol.
Zucchini is a good source of dietary fiber, vitamins, and minerals.