You can either boil or roast the sweet potatoes. I prefer to roast them as the skins are then super easy to remove, but you can also peel them first and then boil them, which is quicker. Boil: Peel the potatoes, cut into cubes and place into salted cold water. Bring to boil and cook until tender (about 15 minutes). Roast: Preheat the oven to 400F / 200c. Place the potatoes on a baking sheet and cook til tender (about 45 minutes). Remove the skins. However way you cook them, be sure to remove the skins as these can be tough to eat.