Mix together the oats, milk, salt, and butter in a small saucepan over medium heat.
Stir the mixture until it begins to bubble and the oats soften. This should take about 5 minutes and the mixture should look thick and creamy. Add more milk or water if you prefer a thinner oatmeal.
Add in any mix-ins that you desire. Sugar, cocoa powder, brown sugar, or peanut butter make great sweet mix-ins to add. Alternatively, you can consider cheese and herbs for savory oatmeal.
Pour the cooked oats into a bowl. Add in any other mix-ins as desired such as nuts, dried berries, or bacon.