Treat them like winter squash. They taste the same. Just remember to remove any strings of you use them for a pie.
The jewel and garnet sweet potatoes are the ones sold as canned "yams" in the stores.
I candy them in a frying pan instead of making the mashed thing other people do. Grandma, and Mom do them that way. Some butter in the pan and fry on medium, turning occasionally. Add a little bit of brown sugar sprinkled on top and cook until caramelized.
We make candied yams for thanksgiving every year, it is tradition. They are so putzy that we only do them once a year. This is my grandmas recipe.
Slice boiled yams into 3/8" rounds (I did slightly thicker rounds this year because I overcooked them and if I cut them any thinner they fell apart.)
Mix about 1/4 c. flour, 1/4 cup brown sugar, salt and pepper.
Blend 1 egg and 1/4 cup of milk.
Heat a frying pan with butter.
Dip sweet potato round in egg mixture, then into brown sugar mixture and fry in pan.
Turn over when browned. Add more butter to pan as needed.
Serve while still warm.
My whole life, I've made candied yams. Mother always used the cans - drain that juice into a frying pan. Add OK and brown sugar. Simmer a long time. Then carefully add in the canned yams and carefully spoon the sauce over them to heat them up.
Mom is sick of the cans with mush and tiny pieces so she's started using fresh sweet potatoes. She likes how they turn out. She peels, cubes, and boils. I did tell her that it's easier to remove the skin afterwards and that most people I knew on the east coast cut them in the bigger rounds or chunks before boiling.
I never could much get into the sweet potato casserole. Sweet potato pie is good, though.