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Juicy caramelized onion burger with grilled beef patty, sweet onions, and fresh slices on a toasted bun.
Maryam

Caramelized Onion Burger

Sweet, jammy onions piled high on a juicy beef patty with melty Gruyere for the ultimate backyard burger upgrade.
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Prep Time 10 minutes
Cook Time 35 minutes
Total Time 45 minutes
Servings: 4 servings
Course: Dinner, Main Course
Cuisine: American
Calories: 680
Ingredients Equipment Method Notes

Ingredients
  

For the Caramelized Onions
  • 2 large yellow onions halved and sliced 1/4-inch thick
  • 2 tbsp unsalted butter
  • 1 tbsp olive oil
  • 0.5 tsp kosher salt
  • 1 tsp balsamic vinegar optional, for depth
For the Burgers
  • 1.5 lb ground beef 80/20 blend, cold
  • 1 tsp kosher salt plus more for seasoning
  • 0.5 tsp black pepper freshly ground
  • 4 oz Gruyere cheese thinly sliced
  • 4 brioche buns split
  • 2 tbsp mayonnaise for toasting buns

Equipment

  • Large Skillet or Cast Iron Pan
  • Spatula
  • Instant-read thermometer (optional)

Method
 

Caramelize the Onions
  1. Melt butter with olive oil in a large skillet over medium-low heat. Add sliced onions and salt, tossing to coat. Cook for 25-30 minutes, stirring every 5 minutes, until onions turn deep golden brown and jammy. If they threaten to burn, add a splash of water. Stir in balsamic vinegar at the end if using. Transfer to a bowl and wipe out the skillet.
Cook the Burgers
  1. Gently form beef into four 6-oz patties, slightly wider than your buns. Press a shallow dimple in the center of each. Season both sides generously with salt and pepper.
  2. Heat the same skillet over medium-high heat until smoking. Add patties and cook without moving for 4 minutes until a deep crust forms. Flip, top with cheese, and cook 3-4 minutes more for medium, or until internal temperature reaches 160 degrees F. Transfer to a plate and rest for 3 minutes.
  3. Spread cut sides of buns with mayonnaise. Toast in the hot skillet, mayo-side down, until golden and crisp, about 1 minute.
  4. Place patties on bottom buns, pile high with warm caramelized onions, and cap with top buns. Serve immediately with your favorite sides.

Notes

Don't rush the onions - medium-low heat and patience yield the sweetest results. For extra richness, stir a tablespoon of cream into the finished onions. The patties can be formed and refrigerated up to 4 hours ahead; let sit at room temperature 15 minutes before cooking.