Dinner

French Onion Cheeseburger Recipe

ByCleo Brixton November 9, 2025November 9, 2025

Introduction

The French onion cheeseburger is a delicious twist on a classic favorite, combining sweet caramelized onions with rich gruyère cheese. This recipe brings together savory flavors and fresh watercress to create a mouthwatering burger experience.

A close-up of a juicy burger with a shiny brown top bun sprinkled lightly with sesame seeds. The burger has four visible layers: a soft golden-brown bottom bun, a thick, cooked beef patty covered in melted white cheese, dark caramelized onions on top, and fresh green leafy lettuce crowning the stack. The burger rests on a white wooden board next to a small silver spoon holding grainy yellow mustard. The background is a white marbled texture. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

2 tbsp butter
1 tbsp oil
1 onion, thinly sliced
½ tbsp light brown soft sugar
1 tsp cider vinegar
1 tbsp wholegrain mustard
2 beef burgers
2 slices gruyère
2 brioche buns
2 handfuls watercress

Instructions

Step 1: Put the butter and oil in a large non-stick frying pan. Add the onion and fry over medium heat for 15 minutes or until golden and sticky.
Step 2: Stir through the light brown soft sugar, cider vinegar, and wholegrain mustard, then remove from heat.
Step 3: Heat the grill to medium-high. Place the beef burgers on a baking sheet and grill for 5-8 minutes on each side until cooked through.
Step 4: For the last minute of grilling, top each burger with a slice of gruyère and grill until the cheese is bubbling and melted.
Step 5: Lightly toast the brioche buns under the grill.
Step 6: Assemble the burgers by placing each beef patty on a bun, topping with the sticky onions, and dividing the watercress equally over the top before serving.

Tips & Variations

Use sharp cheddar instead of gruyère for a different cheese flavor.
Add a splash of red wine to the onions for extra depth.
Swap beef burgers for turkey or veggie patties for a lighter option.
Serve with a side of crispy fries or a fresh salad.

Storage

Store any leftover cooked burgers and onions separately in airtight containers in the refrigerator for up to 2 days. Reheat the burgers gently under the grill or in a skillet to prevent drying out. For best quality, assemble the burger fresh before serving.

How to Serve

A close-up of a juicy burger with three visible layers on a white plate on a white marbled surface. The bottom layer is a thick, grilled beef patty with melted white cheese dripping over it, topped with caramelized onions that are dark brown and glossy. Above this, there is a fresh layer of bright green leafy lettuce. The top layer is a shiny, golden-brown sesame seed bun slightly domed and soft-looking. To the left of the burger, there is a silver spoon with grainy mustard, and the whole scene is lit softly to highlight the textures and colors. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I make the caramelized onions ahead of time?

Yes, the onions can be made a day in advance and stored in the refrigerator. Reheat gently before assembling the burgers.

What can I use if I don’t have gruyère cheese?

Swiss cheese, mozzarella, or sharp cheddar are good substitutes that melt well and complement the onions.