My new favorite way to prepare sweet potatoes: slice them about an inch thick, boil them for 20-25 minutes, let them drain. Then mix 4 cloves of garlic with 3 tbsp melted butter. Drizzle over the sweet potatoes, then sprinkle a little salt over. (I like coarse salt.) Then broil for a few minutes, add some parmesan, and broil a little more.