Preheat your oven to 400°F (200°C) and lightly grease the 9x13-inch baking dish with olive oil.

Peel and chop the sweet potatoes into cubes, and toss them in the prepared baking dish with olive oil, garlic powder, rosemary, salt, and pepper. Bake for 30 minutes until tender.

While the sweet potatoes are baking, heat a skillet over medium heat, add olive oil, and brown the ground turkey with garlic powder, rosemary, salt, and pepper for about 5-7 minutes.

Chop the zucchini and mix it with the browned turkey after removing the sweet potatoes from the oven. Combine evenly.

Drizzle the mixture with olive oil, sprinkle with Parmesan cheese, and return to the oven for an additional 10 minutes until golden.

Let the casserole cool for a few minutes before serving warm.