As an ingredient in soups, stews or casseroles, yams benefit from gentle cooking over a long period to soften them and bring out their flavor. They're equally delicious as a side dish, and a slow cooker is a convenient method of preparing them, especially for large meals when a main dish such as a turkey may be taking up valuable oven space.
Open the canned yams and drain out the fluid. If you're using whole yams, cut them into rough chunks or slices.
Melt butter or margarine, using a stove or microwave oven; use about 1 1/2 tablespoons of butter per 16-ounce can of yams. Mix the butter together with about one-half teaspoon of cinnamon and one-half cup of sugar for each can of yams.
Place the sweet potatoes in the slow cooker. Spread the butter, sugar and cinnamon mixture evenly over them.
Close the lid of the slow cooker. Set it to low heat and allow to cook for six to eight hours. Periodically check the yams; they're done when the flesh is soft and tender.