Combine the oats, water, and salt in a medium saucepan and bring just to a boil. Reduce heat, cover, and just barely simmer about 5 minutes until done. If using steel cut oats, follow the directions on the packaging for cooking time.
Divide oatmeal into 4 serving containers. Top each serving with brown sugar, 1/2 tsp butter, and 1/4 tsp cinnamon. Stir well. Serve with a little milk or cream if desired.
When making this just for myself, I put one serving in my cereal bowl, and the rest into microwavable storage containers and refrigerate. That way it's ready for me each morning and can be heated up in less than a minute. A great idea for busy school mornings.