Give your mashed potatoes a little something extra with the addition of caramelized onions, Gruyère cheese, and fresh parsley. It takes only seven ingredients and two simple steps to make rich, fluffy mashed potatoes. So what happens when we added three more ingredients and one easy step? We ended up with this savory take: the Caramelized Onion Mashed Potato Bake.Even in the South, we know that mashed potatoes should be more than just an excuse to eat gravy. By infusing creamy, dreamy potatoes with caramelized onions and nutty Gruyère, then finishing them in the oven, we’re making a statement: No gravy needed here. For the absolute creamiest texture, use warm liquids whether stock, cream, or milk instead of cold liquids when you begin mashing the potatoes. Serve this potato casserole recipe at your next dinner party with juicy pork tenderloin and home-style green beans, and prepare to really wow the crowd.