Ingredients

• ●1.5 lbs Ground beef
• ●4 oz, grated Gruyère cheese
• ●4 Brioche buns
• ●2, thinly sliced Large onions
• ●2 tablespoons Balsamic vinegar
• ●1 tablespoon Brown sugar
• ●1/2 cup Mayonnaise
• ●1 teaspoon Truffle oil
• ●1 clove, minced Garlic
• ●2 tablespoons Olive oil
• ●to taste Salt
• ●to taste Black pepper

Instructions

1. 1Prepare the balsamic caramelized onions: Heat olive oil in a large skillet over medium heat. Add sliced onions and cook, stirring occasionally, until softened and lightly browned, about 15-20 minutes.
2. 2Add balsamic vinegar and brown sugar to the onions. Stir well and continue cooking until the onions are deeply caramelized and the liquid has reduced to a glaze, about 5-10 minutes. Season with salt and pepper to taste. Set aside.
3. 3Make the truffle aioli: In a small bowl, combine mayonnaise, truffle oil, and minced garlic. Mix well and set aside.
4. 4Form the ground beef into 4 patties. Season with salt and pepper.
5. 5Prepare the Gruyère crusts: Heat a non-stick skillet over medium heat. Place 1/4 of the grated Gruyère cheese in small circles on the hot skillet. Let the cheese melt and crisp up, about 3-5 minutes. Carefully remove the cheese crisps from the skillet and set aside.
6. 6Cook the burger patties: Grill or pan-fry the burger patties to your desired level of doneness.
7. 7Assemble the burgers: Spread truffle aioli on the top and bottom halves of each brioche bun. Place a cooked burger patty on the bottom bun. Top with balsamic caramelized onions and a Gruyère cheese crisp. Place the top bun on the burger and serve immediately.