01 - Heat oven to 425°F and grease a standard muffin tin. Divide twenty-four tots among six wells, four per well. Bake about ten minutes until soft enough to press, then press over each base and partway up the sides. Bake again until the cups hold their shape.
02 - Cook beef and onions together, breaking up meat, until beef reaches 160°F. Drain fat and stir in cooked bacon, ketchup, mayonnaise, mustard and seasoning.
03 - Fill potato cups modestly, add cheddar and mozzarella and bake until centers reach 165°F and cheese melts. Serve extra filling alongside rather than piling it above the cups.
04 - Rest until firm enough to lift with a spoon. Loosen the edges and support each base when serving.