Heat a large skillet over medium heat. Add oil to pan. Add sliced onion and 1/8 teaspoon salt; cook 18 minutes or until golden, stirring occasionally.
Combine 1/8 teaspoon salt, beef, and next 4 ingredients; toss gently. Divide mixture into 4 equal portions, shaping each into a 1/2-inch-thick patty.
Place patties on a grill rack coated with cooking spray; grill 4 minutes on each side or until desired degree of doneness. Top each patty with 1 tablespoon cheese during last 2 minutes of cooking.
Place rolls, cut sides down, on grill rack; grill for 1 minute. Place bottom halves of rolls on 4 plates; top each serving with 1 lettuce leaf, 1 tomato slice, 1 patty, 1/4 cup onion mixture, and 1 roll top.
It's a good burger, but not much more. Can't say I really noticed any flavor from the grated onion, especially when you consider that it's topped with a large number of onions. Truth be told, there is little to no flavor apparent from the garlic and worcestershire. Like I said, decent burger, but I probably won't go through the trouble of making it again.
Good, solid burger - the extra flavors from the onions & garlic within the burger, plus the caramelized on top were fantastic. I used regular blue cheese from the store and next time I think I would mix in the cheese to the burgers themselves just for preference. Otherwise, I would definitely make again for a quick & easy weeknight meal - enjoy!
These burgers are tasty and simple to prepare. My family and I thought we could do without the onions--they didn't seem to add much to the flavor. Served these alongside some potato wedges--a quick and tasty weeknight meal!