Preheat the oven to 350°. Butter a large, shallow oven safe dish. Arrange the sweet potatoes overlapping the slices slightly. Pour 1/2 cup of the water over the sweet potatoes. Cover with foil and bake for about 40 minutes, or until just tender.
Mix the melted butter with the bourbon or Vannila. Spoon the mixture over the sweet potatoes. Increase the oven temperature to 425°. Season with salt and black pepper and bake in the upper third of the oven for about 25 minutes, basting halfway through cooking, until the bourbon mixture is almost completely absorbed.
In a saucepan, combine the cranberries, the remaining 1/2 cup of water and the brown sugar and med-heat until the cranberries start to burst, about 10 minutes. Drain the cranberries, keep the liquid.
Stir the cayenne and cinnamon into the cranberry liquid and spoon it over the sweet potatoes. Bake in the upper third of the oven, basting well after 5 minutes, for 20 minutes longer, until the potatoes are glazed and most of the liquid is gone. During the last 5 minutes of baking, scatter the cranberries on top. Serve.
These can be made a head of time, then warmed before serving.