In a large saucepan, melt butter over medium heat. Add oats and toast for 2 minutes, stirring often. Add boiling water, reduce heat to medium-low, and cover and cook 25 to 30 minutes. Do not stir.
Add milk and salt (if using), stir, cover, and cook for an additional 15 to 20 minutes. Remove from heat and allow the oatmeal to sit undisturbed for 10 minutes before serving.
Recipe Notes
Oats have a tendency to absorb liquid, so if you feel like your oatmeal is dry, feel free to add a splash of milk.