In a large skillet over medium heat, heat butter and olive oil.
Add onions, salt, pepper, thyme and bay leaf. Saute on medium heat for about 30 minutes or until onions are caramelized. Stirring occasionally.
Add broth, brown sugar, and balsamic vinegar. Stir with a spoon until sugar dissolves. Lower the heat to very low, keep warm until ready to serve.
To make homemade burger patties:
In a large mixing bowl combine ground beef, Worcestershire sauce, garlic, parsley salt and pepper. Mix it all together with hands or mixer.
Divide mixture into 4 equal portions and form them into patties. Make sure to make the center a little thinner than the edges for even grilling.
Grill on a medium-high heat for about 5 minutes on each side. Few minutes before patties are done grilling add sliced cheese on top.
To make caramelized onion burger:
Place grilled patties over bottom bun, add lots of caramelized onions, and garnish it with fresh arugula leaves, cover with top bun and enjoy!
Video
Notes
Don’t be alarmed by the onions! Two may sound like a lot, but they cook down significantly and add incredible flavor. I actually recommend making extra—they’re delicious in sandwiches, salads, or even mixed into scrambled eggs the next day.
Make a dent in the center. Before cooking, press a small indentation into the middle of each patty with your thumb. This helps the burgers cook evenly and prevents that puffy, dome-shaped center.
Use a thermometer! For safe and juicy burgers, aim for an internal temperature of 160°F (71°C). No guesswork—just perfectly cooked patties every time.