Let the oatmeal soak in a bowl of water for 12 hours before preparing it.
The next day, drain the water from the oatmeal and place the oatmeal in a saucepan with milk and butter. Bring it to a boil and cook on low for 20-25 minutes (or until softened), stirring occasionally.
Take the saucepan off the stove, stir in the sugar, season with nutmeg and cinnamon and stir in the crème fraîche.