Beef Burger with Caramelized Onions

Ingredients

• 2 tablespoons unsalted butter
• 1 tablespoon olive oil
• 2 large yellow onions, thinly sliced
• 1/2 teaspoon salt
• 1/2 teaspoon sugar
• 1 tablespoon balsamic vinegar
• 1 1/2 pounds ground beef, 80/20
• 1 teaspoon salt
• 1/2 teaspoon black pepper, freshly ground
• 4 slices cheddar cheese
• 4 hamburger buns, split
• 2 tablespoons mayonnaise
• 4 leaves lettuce
• 4 slices tomato

Method

1. 1

   Melt the butter with olive oil in a 9-inch skillet over medium-low heat.

2. 2

   Add the sliced onions and salt, stirring to coat. Cook, stirring occasionally, until deeply golden and soft, 25 to 30 minutes, reducing heat if they brown too quickly.

   25:00 · Caramelize onions
3. 3

   Stir in the sugar and balsamic vinegar, scraping up any browned bits, and cook 2 minutes more. Remove from heat and set aside.

   2:00 · Finish onions
4. 4

   Divide the ground beef into 4 equal portions and gently shape into patties slightly wider than the buns, about 3/4 inch thick. Season both sides with salt and pepper.

5. 5

   Heat a clean 9-inch skillet or grill pan over medium-high heat until very hot.

6. 6

   Cook the patties until a deep crust forms on the bottom, about 4 minutes, without pressing down.

   4:00 · Sear first side
7. 7

   Flip the patties and cook 3 to 4 minutes more, topping each with a slice of cheddar during the last minute so it melts, until internal temperature reaches 160°F.

   3:00 · Sear second side
8. 8

   Toast the split buns, cut side down, in the hot skillet until golden, about 1 minute.

   1:00 · Toast buns
9. 9

   Spread mayonnaise on the bun bottoms and layer with lettuce and tomato. Add the cheesy patties and top generously with caramelized onions. Cover with bun tops and serve.