Heat a medium saucepan over medium heat, add the butter and allow to melt. Add the oats and pumpkin pie seasoning to the pan stirring occasionally, until the oats are toasted, about 3 minutes.
Stir in the salt and 2 cups of water. Bring to a boil then reduce to medium-low heat and cook, stirring occasionally, until the oats are tender, about 15 minutes. Add the pumpkin puree and stir to combine.
Divide among bowls and top with a splash of milk, walnuts, brown sugar and a pinch of cinnamon.