This preparation of au gratin potatoes eschews cheese in favor of spicy horseradish. Trust us, you won’t mix the extra dairy (or calories). And better yet? Set aside just 10 minutes to chop and prep, then let the oven do the rest of the work. You won’t believe how easy it is: First, butter a casserole dish, then combine the remaining five ingredients in a bowl before pressing it into the pan. Bake for 25 minutes with foil covering the dish, then another hour or so without the foil. Serve with a meaty main and a green salad or vegetable for a hearty, comforting meal.