Preheat oven to 350° F.
Chop ends off zucchini; cut in half lengthwise and use a spoon to scoop out the insides. (Reserve for another recipe.) Place prepared zucchini in 9x13 inch baking pan.
In a small mixing bowl, combine ricotta with 1/2 Tablespoon Italian seasoning and 1/2 teaspoon salt. Spoon mixture evenly into zucchini boats.
In a medium skillet, heat olive oil over medium heat. Add the onion and garlic and sauté 1-2 minutes, until garlic is fragrant. Add the remaining veggies, 1/2 Tablespoon Italian seasoning, 1/2 teaspoon salt, and 1/2 teaspoon pepper. Sauté 5 minutes, until vegetables are al dente.
Divide sautéed vegetables evenly among zucchini boats; top with shredded mozzarella and Parmesan.
Bake at 350° 35-45 minutes, until zucchini is tender.