1 Heavy aluminum foil on a piece of paper and a bag of garlic. Bake at 400 degrees Fahrenheit and preheat the oven for about 45 minutes or until soft. Open it and let it cool until it is visible. When lilacs and malt are prepared with potatoes. 5 Wash and put the potatoes in cold water. There is no need to peel potatoes unless you want to. 7 In a large hot pot (or), slowly cook the dried sweet potatoes for about 20 minutes. Turn off the fire and you can eat. It's my pleasure to serve you.