French Onion Burgers with Bacon and Cheese
(1) 2 tablespoons butter
(2) 2 tablespoons olive oil
(3) 3 cups onions, thinly sliced
(4) 2 tablespoons thyme, fresh and chopped finely
(5) 2 teaspoons sugar
(6) 2 teaspoons salt
(7) 3 teaspoons pepper, ground, divided
(8) 1 pound ground chuck
(9) 1 pound ground sirloin
(10) 4 ounces pancetta, diced, fried and drained
(11) 4 ounces Gorgonzola, crumbled
(12) 1 tablespoon Worchester sauce
(13) 8 slices gruyere cheese
(14) Â½ cup mayonnaise
(15) 8 slices tomato, heirloom variety
(16) 6 Brioche hamburger rolls
In a medium saucepan over medium heat, melt butter and olive oil. Add onions and thyme, reduce heat to low and cook covered for about 10-15 minutes, until onions are softened, but have no color. Remove cover, add sugar, salt, 2 teaspoons pepper and cook for 10-15 minutes until onions have caramelized, but not burned. Take off heat and let cool.
Prepare a medium-hot fire in a charcoal grill with a cover, or preheat a gas grill to medium-high.
To make the patties, combine chuck, sirloin, pancetta, Gorgonzola, Worchester sauce, remaining teaspoon pepper and two thirds of the onion filling. Handling the meat as little as possible to avoid compacting it, mix well. Divide the mixture into 8 equal portions and place on a tray.
When the grill is ready, brush the grill rack with vegetable oil. Place the patties on the rack, cover and cook 5-7 minutes. Brush each side of the hamburger bun with olive oil and place on the grill at the same time you flip burgers to the second side, Cook burgers for another 5-7 minutes or until the juices run clear when the patties are pierced in the center. Top with one slice of cheese each for final 3 minutes of grilling.
Mix mayonnaise and remaining third of onion mixture.
To assemble the burgers, spread 1 tablespoon of mayo onion mixture on bottom of bun; add 1 tomato slice, top with the burger, and top bun.