Preheat the oven to 350°F (175°C).

Grease a 9x13-inch casserole dish with olive oil or cooking spray.

In a large skillet, heat olive oil over medium heat. Add chopped onion, green pepper, and diced sweet potatoes, sautéing for 8-9 minutes. Stir in minced garlic in the last minute.

Transfer the sautéed vegetables to the prepared casserole dish and spread evenly.

In the same skillet, cook turkey sausage over medium heat until browned, breaking it into small pieces. Drain excess fat and mix with the sautéed vegetables.

In a mixing bowl, whisk together eggs, milk, thyme, salt, pepper, and shredded cheese until smooth.

Pour the egg mixture evenly over the sausage and vegetable blend in the casserole dish. Stir gently to combine.

Bake in the preheated oven for 40-45 minutes, or until the center is firm and lightly golden.

Allow to cool for 5-10 minutes before slicing and serving.