Preheat the oven to 175C.
Rub the outside of the sweet potatoes with oil. Wrap the potatoes individually in foil. Heat a frying pan and bake the potatoes for 45 to 60 minutes or until you can easily prick a fork in them. Remove from heat and allow to cool.
Mix the flour, sugar, baking powder, cinnamon, nutmeg and salt in a bowl. In another bowl, mix the milk, eggs and melted butter. Then mix in the dry mixture.
Peel the baked sweet potatoes and mash with a sharp fork. Gently mix three quarters of the mashed sweet potatoes into the batter. If necessary, add extra milk. The batter should be thick, but easy to pour.
Heat a buttered pan over medium heat. Pour about 1/4 cup of batter into the pan; bake until bubbles begin to form, about 3 to 4 minutes.
Flip pancake and bake two more minutes. Repeat with remaining batter.
Serve pancakes with maple syrup.