Combine the butter, molasses, brown sugar and cayenne in a medium saucepan and cook over medium heat until smooth, about 5 minutes. Increase the heat to high, add the bourbon and cook for 2 minutes to allow alcohol to burn out. Season with salt and pepper.
Put the potatoes in a large baking dish, pour the molasses mixture over and toss to coat. Roast in the oven, stirring a few times, until the potatoes are cooked through and glazed, about 20 minutes. Remove to a platter and top with the pecans.
Alternatively, this can be done in a large saute pan: Melt the butter, molasses, brown sugar and cayenne over medium heat. Add the bourbon and let the alcohol cook out. Add the potatoes and cook until glazed over medium-high heat. Transfer to a platter and top with the pecans.
The potatoes can either be roasted or boiled to par-cook them.