Place steel cut oats, ground flax seeds (if using) and salt in slow cooker and stir to combine.
*Do not substitute quick cooking, instant or rolled oats
Leftover oats can be stored in the refrigerator (once cooled completely). To reheat, spoon desired amount of oatmeal in a microwave safe bowl. Top with 2-3 tablespoons of additional milk or water. Microwave on high for 1.5-2 minutes or until heated through. Add additional milk and continue to cook, until desired consistency. Alternatively, oats can be reheated in a small saucepan over medium heat.