Preheat your oven to 350 F (180 C). Butter an 8-inch pan.
In a large mixing bowl add eggs, salt, pepper, and seasoning and whisk for 30 seconds.
Add milk and cheese and whisk to combine. Add sweet potato and spinach and mix.
Transfer this mixture to prepared baking dish and bake for 45-50 minutes, until eggs are set. Remove from oven and let cool for 10 minutes before cutting.
Enjoy!