A yam recipe that's easy to make at the last minute.
Peel the yams (or sweet potatoes) the night before cooking.
After peeling the potatoes, slice them into 1/2 inch slices.
Put the yams into a gallon-size (or two quart-size) baggies and store in the fridge until the next day.
If you prefer, save the marshmallows until last. Then preheat the oven to 350 degrees. Put the yam mixture into a foil pan after cooking on the stove. Then place the marshmallows on top, and bake just until they are melted. Remove from the oven, and the yams are ready to eat.