Preheat oven to 350 F and lightly grease the inside of a 2 quart (10 cup) casserole dish 8x8 baking pan. Set aside.
In a large bowl, whisk the eggs and milk until combined. Stir in applesauce, maple syrup, vanilla, cinnamon and flax seeds. Gently fold in oats followed by any add-ins.
Spread mixture evenly into pan and top with additional add-ins.
*you can use mashed bananas instead but it will have more of a banana taste or add another 1/3 cup apple cider or milk instead
Oatmeal will keep in the refrigerator in a covered container, for up to 3 days.
** To make flax eggs for vegan:
Each flax egg is 1 Tablespoon of ground flax seeds + 2.6 Tablespoons water
For 3 flax eggs: Mix 3 Tablespoons of ground flax seeds with 8 Tablespoons water. Let it sit for 5 minutes or until thickened.