In a medium saucepan, bring water, milk, oats, and salt to a boil.
Reduce heat and cook until hot.
Meanwhile, beat an egg and temper it by adding a bit of the hot oatmeal into the bowl with the egg and mix well. Add a bit more hot oatmeal to the egg and then pour the egg mixture into the pot with the oatmeal.
Once oatmeal has reached desired consistency after at least 10 minutes, remove from heat, stir in vanilla and butter, and let stand 2 minutes before serving.
I like to top mine with a chopped date, pecans or walnuts, brown sugar, and a drizzle of cold milk.