A Minnesota-ism
Or at least I never heard it before moving to Minnesota. Take a hot sandwich, such as turkey or roast beef, put mashed potatoes on top, and then cover that in gravy and what do you have? I'd call it a mess, or maybe inedible, and certainly unnecessary. Yet that is what gets called a commercial here. Turkey Commercial, Beef Commercial, and I don't know what other variations there are and I'm not sure I want to.