- Preheat oven to 350 °F (175 °C).
- Boil yams in skins until about half done.
- Drain water from yams, remove skins, and cut in cubes.
- Place cubes in a greased baking dish and dot with margarine.
- Make a syrup by boiling brown sugar, water, and vanilla together. Pour over the yams.
- Bake for 45 to 50 minutes, basting frequently with syrup. Cook until yams are tender.