Crusty Seared Beef Burgers with Gruyère and Caramelized Onions

1. Caramelize the onions

Begin by heating 2 tablespoons of canola oil in a 12-inch sauté pan over medium heat. Add the sliced red onions and cook them for about 8 to 10 minutes until they become tender and start to brown. The onions should be stirred occasionally to ensure even cooking.

2. Add sugar and continue caramelizing

Once the onions are tender, sprinkle them with 1 teaspoon of sugar. Reduce the heat to low and continue to cook the onions for another 10 to 15 minutes until they are deeply browned and caramelized.

3. Deglaze with vinegar

Add 1 tablespoon of red wine vinegar to the pan with the caramelized onions and cook for about 30 seconds. This will deglaze the pan and add a nice tangy flavor to the onions. Remove the onions from the heat and set them aside.

4. Prepare beef patties

In a small bowl, combine 1.5 teaspoons of dry mustard powder with 1.5 teaspoons of kosher salt and 0.5 teaspoons of freshly ground black pepper. In a medium bowl, mix this mustard mixture into the ground beef until evenly distributed. Shape the beef mixture into four equal patties. Place the patties on a plate and freeze them for about 15 minutes. This will help them hold their shape during cooking.

5. Sear the patties

While the patties are chilling, heat 1.5 tablespoons of canola oil in a 12-inch cast-iron skillet over medium-high heat. Take the patties out of the freezer and place them in the hot skillet. Press each patty down with a large metal spatula to ensure a good sear. Cook the burgers for 2.5 to 3 minutes until the bottoms are browned and crusty.

6. Add onions and cheese

Flip the burgers and add the caramelized onions on top of each patty. Sprinkle the grated Gruyère cheese over the onions. Cover the skillet and cook for another 1.5 to 2 minutes until the cheese is melted and the burgers are cooked to your liking.

7. Assemble the burgers

Finally, place each burger on a sandwich potato roll. Serve with ketchup on the side for a classic touch. Enjoy your crusty seared beef burgers with Gruyère and caramelized onions!