Classic Cheeseburgers with Grilled Romaine & Onions
In large skillet over medium-low heat, cook onion in 1 Tbsp. hot olive oil, keeping slices intact. Lightly season with salt and pepper. Cook slowly for 5 minutes, occasionally pressing with spatula to cook evenly. Turn onions carefully, keeping slices intact; cook 5 minutes more, until softened and light brown. (Or brush slices with oil; grill with burgers 5 minutes each side, until browned.)
Build charcoal fire or preheat gas grill for direct cooking. Form ground meat in six 3/4-inch-thick patties. Slightly indent center of each patty. Season patties with salt. Cook patties on covered grill over medium heat for 12 to 14 minutes, until done (160 degrees F), turning once. Top with cheese the last 1 minute of cooking time.
Meanwhile, lightly toast buns on grill. Brush romaine heart with remaining 1 Tbsp. oil. Grill 3 minutes, until browned, turning once. Remove from grill; separate into leaves. Spread buns with mayonnaise. Layer patties, onions, and romaine. Makes 6 burgers.
Home Ground Beef
If using a food processor, freeze meat cubes for 20 minutes. Place 1/2 of the meat cubes in food processor bowl with 1/2 of the pepper. Pulse until coarsely ground. Repeat with remaining half of the meat and pepper. If using a meat grinder, put the chilled chuck roast through the large die of a meat grinder. Add the pepper and grind meat one more time.
Form the ground beef into four 3/4-inch thick patties. Press indentation into each patty, and season on outside with salt.