Preheat the oven to 375 degrees Fahrenheit.
Cut the zucchini in half lengthwise.
Use a metal spoon to remove the inside of the zucchini leaving the shell about ¼ inch thick all around.
Chop the zucchini flesh into small pieces. Place about 1 cup of the flesh in a large bowl.
Set the zucchini in a baking tray with edges.
Heat 1 tablespoon olive oil in a skillet over medium heat.
Add the sausage and cook until cooked through, stirring and breaking into small pieces as it cooks.
Pour 2 tablespoons of maple syrup over the sausage and mix.
Remove cooked sausage. Place it in the large bowl with the zucchini flesh.
Use the remaining grease from the sausage or add more olive oil and cook the onions until softened then add the garlic and cook until garlic is fragrant.
Add the onion and garlic to your large bowl.
To your large bowl, add the remaining ingredients: breadcrumbs, tomatoes, basil, parmesan cheese, egg, salt, and pepper.
Mix well and add the stuffing to the zucchini.
Top the zucchini with fresh parmesan cheese.
Add ¼ inch of water to the bottom of the pan.
Bake for 40 minutes.
Let cool before serving.