Boil or roast the sweet potato until tender. Let cool enough to handle, then peel and mash.
To the mashed sweet potatoes, add the butter, egg, and buttermilk.
In a separate mixing bowl, combine flour, baking powder, baking soda, nutmeg, cinnamon, and brown sugar.
Combine wet and dry ingredients (the order doesn't matter so much for pancakes) and mix until just combined.
Heat a large skillet over medium with 1-2 tbs butter. Let it coat the pan, then working with about 1/4 cup batter at a time, fry the pancakes. They'll need about 2 minutes on each side for the edges to crisp up and to get sufficiently golden brown.
Serve warm, topped with real maple syrup, and enjoy!