Blue Cheese-Stuffed Burgers

This blue cheese burger recipe is sure to be a hit on your dining table. These burgers, which appear to be covered in melted cheese, are one of a kind. Breadcrumbs and eggs hold the mixture together and give it a rich taste. Serve with a side dish, grilled vegetables or potato salad. One online reviewer says: "My wife and I love making these burgers on the grill in the summer. We serve it with oven-baked sweet potato fries."
Brush a small nonstick skillet with cooking spray; set over medium-high heat until hot. Add the onion; saute for 5 minutes or until soft. Remove from heat; allow to cool. Combine the onion, beef, breadcrumbs, water, and egg white in a large bowl; mix well. Divide the mixture into 8 equal portions, forming 1/2-inch thick patties. Place 1 tablespoon of cheese in the middle of 4 patties; top with the remaining patties. Press the edges together to seal.Cooking on the grill. Place the patties on a grill rack greased with cooking spray; cook for 4 minutes on each side or until tender.Spread the top half of each muffin with 1 tablespoon of sour cream and set aside. Line the bottom half of the muffins with lettuce leaves; top each with a slice of tomato, a pie, and the top half of the muffin.