Roast Beef - With greens

1 lb roast beef , cooked (prime rib or any cooked leftover beef) 1 1/2 lbs cooked potatoes or 1 1/2 lbs mashed potatoes 5 shallots , peeled and julienne cut[...]

1 (12 ounce) can roast beef 1 medium onion , diced 8 ounces cheddar cheese , grated, divided use 8 ounces monterey jack pepper cheese , grated, divided use 12[...]