Cheeseburger-Style Meat Loaf Sandwich

Preheat oven to 350°. In a large bowl, combine bread crumbs, egg, onion, pickle, milk, 2 tablespoons ketchup, 1 tablespoon mustard, salt and pepper. Add beef; mix well. Shape into a 4x5-inch loaf and place in a 2-quart baking dish. Bake 1 hour and 10 minutes or until done (165°). Remove from oven; let stand 5 minutes. Turn oven to broil.

Meanwhile, for sauce: Stir together remaining 3 tablespoons ketchup, 1 tablespoon mustard and the mayonnaise. Chill, covered.

Cut bread into eight 3/4-inch-thick slices. (You may not use the whole loaf.) Lightly butter both sides of bread and place on one end of a large baking sheet. Broil 4 to 5 inches from the heat source for 1 to 2 minutes or until lightly toasted; turn slices. Slice meat loaf into four 5-inch long slices. Place on other end of baking sheet and top with cheese. Broil 1 to 2 minutes more or until bread is lightly toasted and cheese is melted. Assemble sandwiches using toasted bread, meat loaf, arugula and sauce.