1-First, preheat the oven to 400 degrees F and coat a baking dish with cooking spray. Wash the zucchinis thoroughly and cut them in half lengthwise, then scoop out the flesh to create hollow shells. Season the zucchini shells with 1/2 teaspoon dried Italian seasoning, salt, and pepper, then place them in the prepared baking dish.

2-Next, in a pan over medium-high heat, heat 2 teaspoons olive oil and cook 1 pound mild Italian sausage for 4-5 minutes, breaking it up as it cooks. Add 1/2 cup finely diced onion and cook until softened, about 4 minutes, then add 1 teaspoon minced garlic and cook for 30 seconds while seasoning with salt and pepper.

3-Stir in 2 cups marinara sauce and simmer for 5 minutes to blend the flavors. Carefully spoon the meat mixture into the zucchini shells, top with 3/4 cup shredded mozzarella cheese, and bake for 25 minutes, or until the zucchini is tender and the cheese is golden brown.

4-Finally, remove from the oven and sprinkle with 1 tablespoon chopped parsley before serving. For vegan adaptations, replace cheese with a plant-based variety, and ensure fillings are free from gluten-containing ingredients. This method not only makes the dish customizable but also highlights its nutritional benefits, as detailed in resources like benefits of zucchini.