Combine all of the ingredients except the coconut oil or butter in a large bowl. Cover and refrigerate overnight or for at least 8 hours.
When ready to bake, preheat the oven to 350 degrees F. Place the coconut oil or butter in a 9-inch square baking pan. When the oven is hot, melt the oil or butter by placing the baking dish in the oven for 2-3 minutes. (If using butter, don’t forget or the butter will burn.) Tilt the dish to evenly coat the bottom.
Stir the baked oatmeal mixture well, and then transfer to the dish with the melted oil or butter.
Bake for 40-45 minutes, depending on your oven, or until the oatmeal is golden and just barely cooked through in the center (it will continue to cook once removed from the oven). If you notice the oatmeal is becoming too brown on top but the center is not cooked through, drape with a piece of foil.
Serve warm or allow to cool and store at room temperature. I usually bake at night so breakfast is ready to go in the morning. After a night a room temp, I cover and store in the fridge to prolong freshness.
