PREHEAT OVEN TO 400°F.
IN A LARGE BOWL, COMBINE THE GROUND BEEF, SALT AND PEPPER, WORCESTERSHIRE, AND GRATED ONION AND MIX UNTIL WELL COMBINED.
PRESS BEEF MIXTURE INTO A 12×17-INCH SHEET PAN AND BAKE FOR 25 MINUTES.
COVER WITH CHEESE SLICES AND RETURN TO OVEN UNTIL CHEESE HAS MELTED, ABOUT 2 MINUTES.
WITH A KNIFE OR PIZZA CUTTER, SLICE MEAT INTO 15 SQUARE PATTIES.
PLACE PATTIES ON ROLLS WITH YOUR FAVORITE CONDIMENTS AND TOPPINGS, AND ENJOY!