Ingredients
Method
Directions
- In a small bowl, stir together the mayonnaise and Dijon mustard until smooth. Set aside.
- Heat the butter and olive oil in a skillet over medium-low heat.
- Add the onions and a pinch of salt. Cook, stirring occasionally, for 25 to 30 minutes until soft, deep golden, and caramelized.
- Preheat a grill or skillet/griddle over medium-high heat.
- Season the burger patties lightly with salt and black pepper.
- Cook the patties until browned and cooked to your preferred doneness, turning once or as needed. Cook time may vary depending on patty thickness, cooking method, and whether cooking from frozen.
- During the last 1 to 2 minutes of cooking, top each patty with a slice of Gruyère cheese.
- Avoid pressing down on the patties while they cook, as this can squeeze out flavorful juices.
- Lightly toast the brioche buns until warm and lightly crisp. Toasting helps the buns hold up better and adds texture.
- Let the patties rest for 3 to 5 minutes.
- Spread the Dijon mayo on the toasted buns.
- Assemble the burgers with the patty on the bottom bun, then top with the caramelized onions. Add the top bun and serve right away.
Cooking Details
- Prep: 10 minutes
- Cook: 35 minutes
- Yield: 4 burgers
