Undoubtedly, a potato casserole which incorporates cheese! This recipe for creamy baked Cheesy Mashed Potatoes Casserole combines America's favorite comfort food, the mashed potato together with sour cream, chives AND green onions, shredded cheese, and salty dry-cured country ham or prosciutto! This recipe was created out of necessity. When the holidays come around, inevitably I have more casseroles and last minute dishes to assemble than I'd care to admit. ANYTHING that is CHEAP, SUPER YUMMY, and can be MADE AHEAD is a life saver. The potatoes are a 15-ish minutes cook time boiled, then mashed in the same one pot on the stove top until smooth. If you prefer to cook your potatoes with the use of a slow cooker or an instant pot, by all means bust 'em out! Grab a trusty handheld potato masher or hand mixer and you're ready to mash potatoes! Shredded cheese, fresh snipped chives, a chopped salty ham, and rough chopped green scallions are folded in to create this ULTIMATE loaded potato dish. All are then mounded into a generously buttered baking dish and either baked or covered with plastic film until ready to bake.