Whisk together the first six ingredients (half and half through nutmeg) in a medium sauce pot. Cook over medium-high heat and bring to a boil.
Stir in the steel cut oats and reduce heat to low. Simmer for 15-20 minutes.
While the oats are cooking, add the cranberries, water and brown sugar to a small sauce pot over high heat. Bring to a boil then reduce to a simmer. Cook for 10-15 minutes. Mash cranberries with a wooden spoon or potato masher until you create a puree.
Divide the oatmeal between four bowls and top with the cranberry mash. Sprinkle with additional brown sugar if you wish.