Heat oven to 325 degrees. Bake sweet potatoes 35 to 45 minutes, or until cooked. Remove from oven and let cool. Remove a slice off the top of each potato and scoop out insides of potato. Try to keep the skin intact. Leave a little potato next to the skin. Place potato pulp in a large mixing bowl. Add butter and mash thoroughly. (I use a hand beater.) Add half and half until you have a creamy mixture. Fold in fruit and nuts and carefully put the mixture back into the potato skins. Place on cookie sheet and bake for another 30 minutes at 325 degrees.