Heat butter over medium heat.

Add the oats and stir to coat the oats in butter.

Toast gently in the pan, this takes about 5 minutes.

While the oats are toasting, pour the milk, water, sugar, and salt into a large pot. A large pot helps the oats not get mushy.

Bring the liquid to a simmer over medium heat while you are toasting the oats.

Stir in the oats. Bring to a slow boil, then reduce the heat to low. Partially cover the pot.

Stir occasionally to avoid the oats from getting clumpy and sticking to the pan.

Cook for 25 to 30 minutes, or until the oats have thickened and have softened. It might be a little loose, and that's okay, it will soak up liquid as it cools. Stir in the vanilla bean paste.