Blue Cheese Burger with Caramelized Onions

Blue cheese and beef are a classic steakhouse pairing, and they work just as well in a burger. Tangy, funky blue cheese melts into the hot patty, sweet caramelized onions balance the sharpness, and a handful of arugula adds a peppery, fresh bite.

The onions take the longest, so start them first or make them a day ahead. Our guide to caramelized onions for burgers walks through the process, and the best cheese for burgers explains which blues melt best.

1. Caramelize the onions. Melt the butter in a large skillet over medium-low heat. Add the onions and ½ teaspoon salt. Cook, stirring every few minutes, until soft and deep golden, 30 to 40 minutes. Add a splash of water if they stick. Stir in the balsamic, if using.
2. Form the patties. Divide the beef into 4 portions (6 oz / 170 g each) and shape into patties about ¾ inch thick. Press a shallow dimple into the center of each.
3. Heat the pan or grill. Heat a cast-iron skillet over medium-high heat or preheat a grill to medium-high.
4. Cook the patties. Season with the remaining salt and the pepper. Cook 4 to 5 minutes per side until well browned.
5. Add the blue cheese. During the last 1 to 2 minutes, pile crumbled blue cheese on each patty and cover to soften.
6. Check the temperature. Cook until the patties reach 160°F (71°C). Rest 2 to 3 minutes.
7. Toast and assemble. Toast the buns. Spread with mayo or Dijon, then layer arugula, the patty, caramelized onions and bacon if using. Serve.

• Use a cover. Blue cheese softens rather than fully melts; a lid or dome traps heat to help it along.
• Make onions ahead. Caramelized onions keep 3 to 4 days in the fridge.
• Pick your blue. Gorgonzola dolce is creamy and mild; Roquefort is saltier and sharper.
• Stuff it instead. For a surprise center, seal a tablespoon of blue cheese inside two thin patties.

Approximately 780 calories per serving. This is an estimate.