Cookwith - Bakery-Style Brioche Burger with Caramelized Onions

Ingredients

• 1 1/2 lbs ground chuck (80/20 beef)
• 4 soft brioche burger buns
• 4 slices sharp cheddar cheese
• 1 large yellow onion, thinly sliced
• 2 tbsp unsalted butter
• 2 tbsp mayonnaise
• 2 tbsp Dijon mustard
• 1 tbsp ketchup
• 2 tsp Worcestershire sauce
• 1 tsp smoked paprika
• Kosher salt, to taste
• Freshly ground black pepper, to taste
• 4 large leaves butter lettuce
• 2 medium ripe tomatoes, sliced
• 2 tbsp olive oil