Bacon and Blue Cheese-Stuffed Burgers

Instructions

1. Heat oven to 400°F. 
2. Remove papery outside from garlic (keeping cloves together). Cut off the top third of garlic bulb; drizzle with olive oil. Tightly wrap with aluminum foil. Bake for 35-40 minutes or until garlic is tender. Cool for 15 minutes. Squeeze garlic into a small bowl. Mash with a fork. Set aside 2 tablespoons garlic. Save any remaining garlic for a different recipe.
3. Meanwhile, melt butter in a large, heavy skillet over medium heat. Add onions; cook for 10 minutes, stirring frequently. Reduce heat to medium-low. Cook for 20-25 minutes longer or until onions are golden brown, stirring occasionally, adding a tablespoon water as necessary for a deeper color if desired. Season with salt and pepper to taste. Remove onions from the pan. Keep warm.
4. Combine mayonnaise and 1 tablespoon reserved garlic. Cover and refrigerate until serving.
5. Grease grill grate. Heat grill to medium.
6. Crumble beef over remaining garlic in a large bowl; mix just until combined. Divide beef mixture into eight portions; shape into balls. Form into patties, each about 1/4-inch thick. Place blue cheese into the center of four patties. Sprinkle with bacon. Top with remaining patties; press meat edges to seal. 
7. Grill burgers, covered, over medium heat for 5-8 minutes on each side or until a thermometer inserted into patties reads 160°F. Top with colby. Cover and cook for 1-3 minutes longer or until cheese is melted.
8. Spread mayonnaise mixture on bun bottoms; top with lettuce, burgers, onions and barbecue sauce. Replace bun tops.