3 Ingredient Roasted Potatoes and Onions from The Food Charlatan. These tender roasted potatoes and onions are done SO fast, because instead of adding a whole bunch of spices to make them delicious, you just dump on some onion soup mix and throw it in the oven. The dehydrated onions get all crunchy and glorious! Perfect side dish for Thanksgiving! #roastedpotatoes #potatoes #onions #easy #quick #lipton #onionsoupmix #oven #soupmixes