Description

These French Onion Burgers are juicy, flavorful, and loaded with sweet caramelized onions and melty cheese, all tucked into a toasty bun. Inspired by classic French onion soup, this burger has rich savory notes, a buttery onion topping, and plenty of gooey goodness. Perfect for cookouts, cozy dinners, or when you just want a seriously satisfying burger.

Ingredients

For the Caramelized Onions:

2 large yellow onions, thinly sliced
2 tbsp butter
1 tbsp olive oil
1/2 tsp salt
1/4 tsp black pepper
1 tsp balsamic vinegar (optional, for depth)

For the Burger Patties:

1 1/2 lbs ground beef (80/20 recommended)
1 tbsp Worcestershire sauce
1 tsp garlic powder
Salt and pepper, to taste

For Assembly:

4 burger buns
4 slices Gruyère cheese (or Swiss)
Mayo or garlic aioli (optional)
Fresh thyme or parsley (optional for garnish)

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Instructions

Make the caramelized onions: In a large skillet, heat butter and olive oil over medium-low heat. Add sliced onions and season with salt and pepper. Cook slowly for 25–30 minutes, stirring often, until deep golden brown. Stir in balsamic vinegar at the end if using. Set aside.
Form the patties: In a large bowl, mix ground beef with Worcestershire, garlic powder, salt, and pepper. Divide into 4 equal patties and shape them slightly wider than your buns (they’ll shrink when cooked).
Cook the burgers: Heat a skillet or grill over medium-high heat. Cook the patties for 4–5 minutes per side, or until cooked to your liking. Add cheese slices during the last minute of cooking and cover the pan to melt.
Toast the buns: While the burgers cook, lightly toast the buns in a skillet or under the broiler.
Assemble: Spread mayo or aioli on the buns if desired. Place a burger patty on the bottom bun, top with a generous scoop of caramelized onions, and sprinkle with fresh thyme or parsley. Add the top bun and serve warm.

Notes

Gruyère gives that classic French onion soup flavor, but Swiss, provolone, or white cheddar work too.
To save time, you can caramelize the onions ahead of time and store in the fridge for up to 5 days.
For a fun twist, try adding a spoonful of onion soup mix to the beef mixture.