Preheat the oven to 375°F (190°C). Gather your ingredients and grease your baking dish.

Wash, peel, and slice sweet potatoes into thin rounds, about 1/8 inch thick. Layer them in the greased pie dish.

Drizzle sweet potatoes with cooking oil, sprinkle with salt, pepper, and garlic powder. Bake for about 20 minutes.

Heat oil in a skillet over medium heat; sauté chopped onion and bell pepper until soft, about 5-7 minutes. Add spinach until wilted, then cool.

In a mixing bowl, whisk eggs and milk until smooth. Add salt and pepper, then fold in the sautéed vegetables and half of the cheese.

Pour the egg and vegetable mixture over the crust, ensuring even coverage. Sprinkle remaining cheese on top.

Bake for 28-30 minutes until edges are set and center is slightly jiggly.

Once baked, let cool for 5-10 minutes, slice into wedges, and serve warm.