I set my oven on the lowest setting it would go, which was 160 F (71 C).
As the oven preheated, I mixed my ingredients well in a casserole dish. I covered the dish with foil.
When the oven was ready, I turned it off and put my dish in to sit.
It sat there all day, about 12 hours (I actually forgot that it was in there!). If you can, try to stir occasionally as you cook it. This will prevent the milk from boiling over and the bottom from scorching. This slow cooking is necessary, as it helps turn the milk into a solid instead of causing it to separate.