Go Back

Caramelized Onion Burger Recipe

A savory, restaurant-style Caramelized Onion Burger recipe featuring slowly caramelized yellow onions, a juicy 80/20 beef patty, melted cheese, and a simple garlic aioli — perfect for weeknight dinners or weekend BBQs. This SEO-friendly summary highlights key flavors and encourages clicks without keyword stuffing.
Print Recipe Pin Recipe
Prep Time 20 minutes
Cook Time 10 minutes
Caramelizing onions 40 minutes
Course Main Course
Cuisine American
Servings 4
Calories 1120 kcal

Ingredients
  

For the caramelized onions

  • 3 large yellow onions about 2–2½ lb / ~600 g total, thinly sliced
  • 2 tbsp unsalted butter
  • 2 tbsp neutral oil vegetable, canola, or grapeseed
  • ½ tsp fine sea salt
  • 1 –2 tsp granulated sugar or honey optional, speeds browning
  • 2 tbsp balsamic vinegar optional, for finishing
  • 2 tbsp water or beef stock for deglazing if needed

For the burger patties

  • 1½ lb ≈680 g ground beef, 80/20 blend
  • 1 tsp fine sea salt
  • ¾ tsp freshly ground black pepper
  • 1 tsp Worcestershire sauce optional
  • 1 small shallot minced (optional)
  • 1 tsp Dijon mustard optional

For assembly & toppings

  • 4 burger buns brioche, potato roll, or sesame
  • 4 –6 slices cheese Gruyère, sharp cheddar, Swiss or provolone — plan 1–2 slices per burger depending on preference
  • Butter for toasting buns
  • Lettuce or arugula optional
  • 4 tomato slices ripe but firm
  • Pickles or quick-pickled red onion optional
  • Optional extras: thick-cut bacon cooked crisp, sautéed mushrooms, blue cheese crumbles, pickled jalapeños

Garlic Aioli (optional)

  • ½ cup mayonnaise
  • 1 small garlic clove grated
  • 1 tsp Dijon mustard
  • 1 tsp lemon juice
  • Salt & pepper to taste

Instructions
 

Make the caramelized onions (can be made ahead)

  • Heat a wide, heavy skillet over medium-low heat. Add 2 tbsp oil + 2 tbsp butter and let the butter melt.
  • Add thinly sliced onions and ½ tsp salt; stir to coat. Spread the onions in an even layer.
  • Cook low and slow, stirring every 3–5 minutes. After ~10–15 minutes they will soften; after 30–45 minutes they’ll turn golden-brown and silky. If they stick or the pan looks dry, add 1–2 tbsp water or stock and scrape up the fond.
  • Optional: stir in 1–2 tsp sugar if browning is slow. Finish with 2 tbsp balsamic vinegar off the heat for depth, then set aside. (Refrigerate up to 5 days.)

Prepare patties

  • Keep the ground beef cold. In a bowl gently mix beef, 1 tsp salt, ¾ tsp pepper, and optional Worcestershire, shallot, and Dijon — do not overwork.
  • Divide into 4 equal portions (~6 oz each). Form loose patties about ¾–1" thick and make a slight indentation in the center with your thumb (helps prevent doming). Chill briefly if time allows.

Make the aioli (optional)

  • Mix ½ cup mayonnaise, grated garlic, 1 tsp Dijon, 1 tsp lemon juice, salt & pepper. Refrigerate until ready.

Cook the burgers (cast iron skillet method — recommended)

  • Heat a cast-iron skillet over medium-high until hot. Lightly oil the pan. Pat burgers dry with a paper towel.
  • Place patties in the pan without overcrowding. Sear undisturbed 3–4 minutes to form a crust. Flip and cook 3–4 minutes more for medium-rare to medium (adjust time for thickness).
  • Add cheese in the final 1 minute and cover to melt. Use an instant-read thermometer for precision: 120–125°F rare, 130–135°F medium-rare, 140–145°F medium, 160°F well done (USDA).
  • Let patties rest 2–3 minutes.

Toast buns & assemble

  • Butter cut sides of buns and toast in a skillet or under broiler until golden.
  • Spread aioli or preferred sauce on the bottom bun; add lettuce/arugula (optional). Place the rested, cheese-topped patty on the bun. Generously spoon warm caramelized onions over the cheese. Add tomato slice and pickles if using. Cap with the top bun and serve immediately.

Notes

  • Tips: Use a wide pan for onions — more surface area speeds and evens caramelization.
  • Keep meat cold throughout prep for cleaner sear and juicier patty.
  • Don’t press burgers while cooking — pressing squeezes out juices.
  • Make the onions ahead; they improve overnight in the fridge and save time when assembling burgers.
  • Storage: Caramelized onions: refrigerate up to 5 days or freeze in portions up to 3 months.
  • Cooked patties: refrigerate up to 3 days; reheat gently in a skillet with a splash of water and a lid to retain moisture.
  • Assembled burgers: best eaten immediately; avoid storing fully assembled if possible.
  • Variations: Gruyère & thyme: swap cheese and stir fresh thyme into the onions.
  • Blue cheese & bacon jam: crumble blue cheese onto patties and fold bacon jam into the onions.
  • Mushroom-onion Swiss: sauté mushrooms with the onions; top with Swiss.
  • Veggie/plant-based: use a grilled portobello cap or plant-based patty; cook similarly and use same toppings.