Preheat oven to 400 degrees. Grease a 9×12 baking dish.
Toss diced sweet potatoes in fat and sprinkle with salt
Place sweet potatoes on baking sheet and bake for 20-25 minutes, until soft.
While sweet potatoes are cooking, place a large sauté pan over medium heat. Add breakfast sausage and yellow onion. Cook until no pink remains in meat.
Place meat mixture in baking dish, add sweet potatoes and spinach then add eggs along with salt and garlic powder and mix until well combine.
Place in oven and bake for 25-30 minutes, until eggs are set in the middle.