Fill a large stock pot with water and bring it to a boil.
For each potato, cut a slit in the skin down the length and around the center before placing in pot (this will make the skin easier to remove after cooking)
Boil potatoes 40-45 minutes or until tender, remove from heat and allow to cool.
Once potatoes are cool to the touch, gently remove the skin and put in a large mixing bowl.
Preheat oven to 400°F. Mash potatoes to desired consistency.
Then, add eggnog, raisins and sugar to potatoes. Mix to combine.
Transfer mixture to a greased 9x12baking dish.
Mix together all topping ingredients and cover potato mixture, evenly distributing across the whole dish.
Place small squares of butter over top of dish to melt while cooking. Bake, uncovered, until heated through and topping is lightly browned, 30-35 minutes.