By Jayne Cohen
They started out in three separate piles, our weekday trinity: brisket, skirt steak, or sometimes a thick meat patty (it only became a hamburger when surrounded by a roll): one hill of fluffy mashed potatoes and another of shimmering, bronzed onions. Under my grandmother’s tutelage, I learned the correct way to combine them in a sublime mishmash.
First, of course, stir the onions into the potatoes, adding little spoons of gravy or meat juices to make the mixing easier. Impale the me