Cheddar BLT Burgers with Tarragon Russian Mayonnaise

Ingredients

• 1/2 cup mayonnaise
• 1/3 cup ketchup
• 1 T. red wine vinegar
• 1 T. grated onion
• 1 T. chopped parsley
• 1 T. chopped tarragon
• 1 t. Worcestershire sauce
• 12 ounces thickly sliced bacon
• 2 1/2 pounds ground beef chuck
• 2 t. kosher salt
• 1/2 teaspoon freshly ground pepper
• 2 T. unsalted butter, melted
• 3 ounces sharp cheddar cheese, cut into 6 slices (We used Hook's 2 Year Cheddar)
• 6 Brioche buns, split and toasted
• 6 lettuce leaves
• 6 slices tomato
• 6 thick slices red onion