Preheat oven to 350 degrees. Grease a 2 quart or 8 inch square pan with butter or coconut oil.
Mix together milk, maple syrup, vanilla, egg, cinnamon, nutmeg, sweet potato puree, baking powder, flax, remaining coconut oil, and salt together until well combined. Add in oats and stir just until incorporated and oats are coated.
Bake for 25-30 minutes, until oats are tender and moisture has been absorbed.
Serve warm with additional maple syrup and chopped walnuts if desired.
Leftover baked oatmeal can be stored covered in the fridge for 3-4 days. Reheat in the microwave before serving.
Use any milk you like for this sweet potato oatmeal. I have used regular milk, coconut milk, and almond milk with great success.
I used old fashioned oats for these recipes, but quick-cooking oats work as well. Do NOT use steel-cut oats. Be sure to use certified gluten-free oats for a gluten-free baked oatmeal recipe.
You can use melted butter in place of the melted coconut oil. Or omit both the coconut oil or butter for a lower fat oil.
You can use brown sugar in place of the maple syrup. If you like your oatmeal very sweet use ½ cup maple syrup/brown sugar.
If you don't have Sweet Potato Puree on hand, use canned pumpkin and add in ¼ teaspoon ground ginger for a pumpkin pie version of baked oatmeal.
To Prep Baked Oatmeal in advance: Assemble up to baking and cover and refrigerate for up to 24 hours. Remove from fridge and pre-heat oven to 350 degrees. Bake for 40-45 minutes, or until set.