Garlicky Blue Cheese Spread: Combine mayonnaise, salt, pepper, red wine vinegar and garlic. Mix well and stir in crumbled blue cheese. Store in refrigerator until ready to use.
Burgers: Heat a grill pan on the stove top, or an outdoor grill to medium-high heat. Combine beef, 2 tablespoons barbecue sauce, salt and pepper. Divide and shape mixture into 8-10 3/4"-thick patties (keep the size of your buns in mind as wells the fact that the burgers will shrink quite a bit while cooking when shaping the patties). Grill for 2-3 minutes and then flip. Brush the top side of each burger with remaining sauce. Continue grilling for another 2 minutes and flip burgers again, brushing the other side with additional sauce. Continue to cook and baste until the internal temperature of the burgers reach 160-165 degrees.
To assemble: Lightly spread the bottom half of each bun with Garlicky Blue Cheese Spread and top with a lettuce leaf. Break each bacon piece in half and place on top of lettuce leaves. Place burger on top and drizzle with additional barbecue sauce if desired. Top with a small handful of Crispy Shoestring Onions. Spread remaining Garlicky Blue Cheese Spread on top halves of buns.