The nutrition facts are at Calorie Count!
2 T butter
2 T dark brown sugar
1/4 cup Kahlua
Roast (or you can boil) the yams and then mash with the other three ingredients. Place in a Pam sprayed casserole and bake at 375 F for about 20 minutes.
If you can afford the calories, during the last few minutes of baking, you can either top with more brown sugar or some of those mini marshmallows.
If you're pressed for time or oven space, use good quality canned yams, WITH the liquid. Put all ingredients in a saucepan, boil until the liquid reduces by about half, and pour into a serving dish.
Simple and delicious!