Grilled Bacon Burgers with Caramelized Onion in Rhum Vinegar and Blue Cheese

Ingredients

1 tablespoon butter
1 tablespoon olive oil
2 large sweet onions, halved and thinly sliced
1 tablespoon Balsamic Vinegar
2 large garlic cloves minced
1 teaspoon sea salt
¼ cup solidified bacon grease from hickory smoked bacon
1 pound chuck tender roast, trimmed of all fat and cut in thin strips Black peppercorns
Olive oil, for brushing on the grill rack
1 loaf ciabatta bread, sliced into 5 inch sections and split
20 baby spinach leaves
2 ounces crumbled blue cheese

Instructions

Prepare a medium-hot fire in a charcoal grill with a cover, or preheat a gas grill to medium-high. To make the caramelized onions, preheat a sauté pan over high heat for 3-5 minutes. Add butter to pan and allow to brown quickly, but be careful not to burn. Add olive oil and swirl pan to combine. Add onions and toss to make sure all onions are coated with oil. Reduce heat to low and cook 30 to 40 minutes, stirring occasionally, until the onions are caramelized and most of the liquid is evaporated. Add the vinegar and stir to coat. Remove the pan from the heat and set aside. To make the patties, using the blade of a large chefs knife, mash the minced garlic and salt together to form a paste. Stir the garlic paste and bacon grease together. Coat the beef strips with the garlic bacon grease mixture. Grind the beef strips. Handling the meat as little as possible to avoid compacting it, divide the ground meat into 2 equal portions and form into patties to fit the bread. Set a pepper grinder to coarse and grind the pepper over the patties generously coating each side. When the grill is ready, brush the grill rack with olive oil. Place the patties on the rack, cover, and cook, turning once, until done to preference, 5 to 7 minutes on each side for medium. During the final minutes of grilling the patties, place the rolls, cut side down, on the outer edges of the grill rack to toast lightly. To assemble the burgers, place 10 baby spinach leaves on each bread bottom, place a patty, an equal portion of the caramelized onions and blue cheese on each burger. Add the bread tops and serve.