Throughly wash the sweet potatoes, and leave damp. Wrap in tin foil while still wet so the moisture will steam the skins. Bake at 400 degrees for 2 hours. Allow to rest in foil and cool off.
Then remove the skins and mash with a fork. Add pure maple syrup or honey. Can also add MSPI safe margarine or olive oil, as well as additional spices such as pumpkin pie spice, cinnamon, etc.