Cut zucchini in half lengthwise and scoop out the insides, leaving the shell about 1/4 inch thick. Reserve half of the insides.
In a skillet on medium-high heat, heat 1 Tbsp. olive oil. Saute the onion and garlic until tender, about 4-5 minutes. Add the
Heat the remaining 1 Tbsp. olive oil in a skillet on medium-high heat and crumble the turkey and cook until lightly browned on all sides. Stir in the cooked onion and mushroom mixture. Add the wine to the pan along with the tomatoes, basil, and rosemary. Cook for 1 more minute, then drain excess fat and remove from the heat.
Preheat oven to 375 degrees. Once the turkey mixture has cooled a bit, mix in the parmesan, egg, salt, and pepper. Fill the zucchini shells with the mixture. Fill a baking dish with 1/4 inch water and place the filled zucchini shells in the pan. Bake for 40 minutes until the turkey turns golden brown. Remove from the pan and serve immediately.