Heat oil in a large nonstick skillet over medium-high heat. Add onion, sugar, salt, and pepper to pan. Cook 6 minutes or until lightly browned, stirring occasionally. Add vinegar to the pan; cook 30 seconds, stirring constantly.
Combine cheese and next 5 ingredients (through beef) in a medium bowl; shape meat mixture into 4 (3-inch) patties. Heat a grill pan over medium-high heat. Coat pan with cooking spray. Add patties to pan. Cook 5 minutes on each side or until desired degree of doneness. Place 1 patty on bottom half of each bun; top each patty with 1/4 cup onion mixture and top half of each bun.
This recipe has become a favorite! It's great for an easy, week night burger that is filling and very good! We used angus beef (lean) and it was great!! A little extra tomato paste helps to keep it from being dry. I served it with baked butternut squash fries (a family favorite)
I seriously make these about once a week for my family. The onions are so delicious you could almost just put them on a bun. The tomato paste keeps the burgers nice and juicy and omits the need to add ketchup on top.
YUM! I cooked them in a regular frypan (don't have a grill) and they were delicious. I topped them with Provolone and skipped the bun. Very flavorful. No other condiments necessary. The only issue I had was that they seemed to be very greasy. Unusually so for ground chuck and I think that it might have been from the tomato paste. I had to drain a lot of fat from the pan while cooking and squished the finished burgers with paper towels. They were still very, very good and juicy, and I will definitely make again only with ground sirloin which is lower in fat.
I accidentally put basil in the onions and they turned out just fine. Really wish I could try them grilled. Make these, they are quick, easy, and really really good.