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French onion burgers topped with cognac and balsamic glazed onions and melted Gruyère cheese on a toasted brioche bun.

Gourmet French Onion Burgers With Savory Onion Jam

Rebecca Blumer
Indulge in the ultimate comfort food with these juicy French onion burgers, featuring slow-caramelized onions, melted Swiss cheese, and a fragrant herbed aioli on toasted brioche buns.
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Prep Time 20 minutes
Cook Time 3 hours 22 minutes
Resting 5 minutes
Total Time 3 hours 47 minutes
Course Main Course
Cuisine American, French
Servings 8 burgers
Calories 845 kcal

Equipment

  • Large Dutch oven
  • Cast Iron Skillet or BBQ Grill
  • Mixing Bowls

Ingredients
 

For onions:

  • 4 tablespoons butter
  • 5 pounds onions
  • 1 cup beef broth
  • 1 pinch fresh or dried thyme leaves
  • Sea salt to taste

For the burgers:

  • 3 pounds 80% lean ground beef
  • Sea salt to taste
  • Freshly ground black pepper to taste
  • Garlic powder to taste
  • 8 ounces Swiss cheese
  • 2 tablespoons butter
  • 8 brioche hamburger buns
  • 2 large ripe tomatoes
  • 3 cups baby arugula

For the Herbed Aioli:

  • 1 large whole egg
  • 1 teaspoon lemon juice
  • 1 teaspoon Dijon mustard
  • 1 garlic clove
  • 0.5 teaspoon salt
  • 0.5 cup avocado oil
  • 0.5 cup extra virgin olive oil
  • 2 tablespoons fresh sage
  • 2 sprigs fresh rosemary
  • 2 sprigs fresh thyme

Instructions
 

Slow-caramelized onions

  • Slice the onions into rounds about 1/4 inch to 1/2 inch thick, ensuring even slices for consistent cooking.
  • Melt 4 tablespoons of butter in a large Dutch oven. Add the onions in batches as they wilt, stirring and flipping often.
  • Turn the heat to low, cover, and cook for 2 to 3 hours. Check every 30 minutes to scrape the bottom and ensure nothing scorches.
  • Uncover the pot and pour in 1 cup of beef broth. Add a pinch of thyme and sea salt, stirring until the onions look glossy.
  • Raise the heat slightly and cook uncovered for another 30 to 45 minutes until the liquid evaporates and onions turn deep amber and jam-like.

Patty shaping and seasoning

  • Preheat your BBQ grill or cast-iron skillet. Divide the 3 pounds of ground beef into 8 equal portions.
  • Form wide patties about 5 inches across and press a small indentation in the center with your thumb. Season both sides with sea salt, pepper, and garlic powder.

Searing, melting, and assembling

  • Cook the patties for 3 to 4 minutes on the first side until browned. Flip and cook for another 5 to 6 minutes until cooked through.
  • Spoon 1.5 tablespoons of caramelized onions onto each patty and top with 1 ounce of Swiss cheese. Cover briefly to melt the cheese.
  • Butter the brioche buns and toast them until golden and nutty.
  • Assemble the burgers by placing a tomato slice and arugula on the bottom bun, followed by the patty. Spread herbed aioli on the top bun and serve immediately.

Notes

Safety Tip: Homemade aioli made with raw egg should be kept very cold and consumed within 2 days for safety.
Pro Tip: Always indent the center of your beef patties before grilling. This prevents them from puffing up in the center and ensures they stay flat and cook evenly.
Storage Tip: Caramelized onions can be prepared up to 4 days in advance and stored in the refrigerator. They also freeze well for up to 3 months.
Nutrition information is estimated based on common ingredients and serving sizes and may vary.

Nutrition

Calories: 845kcalCarbohydrates: 34gProtein: 41gFat: 56gSaturated Fat: 22gCholesterol: 188mgSodium: 945mgPotassium: 615mgFiber: 4gSugar: 11gVitamin A: 14IUVitamin C: 12mgCalcium: 32mgIron: 26mg
Keyword caramelized onions, french onion burgers, gourmet burger
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