If you are tight on time or just don’t want to mess with fresh yams, canned yams can be used. I don’t think they are as good as fresh yams, though. Make sure to get plain yams and not ones that are already candied or spiced in the can. Drain the liquid and slice if necessary. Assemble the casserole as in the instructions. These will already be cooked, so just bake them covered with foil for 30 minutes, then check for doneness. When they are soft, remove the foil, increase the oven temperature to finish per the instruction.