Preheat oven to 400 degrees. Spray a 13x9 inch baking dish with non-stick spray.

Using a spoon, scoop centers from zucchini, leaving a 1/4-inch rim to create boats. Drizzle with 1 Tbsp olive oil, then season with salt and pepper.

Bake in preheated oven for 15 minutes.

Meanwhile, heat 1 Tbsp olive oil in a large skillet over medium-high heat. Add onion and sauté for 3 minutes.

Add sausage in crumbles, cook through, breaking up meat during cooking. Add garlic during the last minute.

Remove from heat, stir in tomatoes, 1/3 cup panko breadcrumbs, and Italian seasoning. Season with salt and pepper.

Sprinkle 1/3 cup parmesan over zucchini boats, then evenly divide filling among them.

In a small bowl, mix mozzarella, remaining parmesan, and remaining panko. Sprinkle over the zucchini boats.

Bake until tender, about 10-15 minutes. Garnish with parsley and serve warm.