Burgers with Blue Cheese Mayo and Sherry Vidalia Onions

Preheat grill to medium-high heat.

Combine 1/2 cup blue cheese, mayonnaise, 1 teaspoon thyme, and Tabasco sauce in a small bowl; stir well and set aside.

In a medium bowl, combine ground beef, soy sauce, Worcestershire sauce, steak sauce, and 1 teaspoon pepper.

Mix well.

Divide beef into 4 equal portions, shaping each portion into a 1/2-inch-thick patty.

Sprinkle beef evenly with 1 teaspoon black pepper and salt.

Brush oil evenly over both sides of onion slices; sprinkle lightly with salt and pepper.

Place the patties and onions on grill rack that has been coated with cooking spray; put the cover on the grill.

Grill meat patties for 4 to 6 minutes per side and grill onions for 3 to 4 minutes on each side.

Meanwhile, in a grill pan sprayed with cooking spray, quickly saute mushrooms over medium heat until most of the liquid cooks out of the mushrooms.

Set patties aside; keep them warm.

Place the onion slices and sauteed mushrooms in a zip-top plastic bag with vinegar and the remaining thyme; seal.

Let stand 5 minutes.

Spread cut sides of buns evenly with mayonnaise mixture.

Arrange lettuce and tomato on bottom half of each bun; top with 1 patty, 1/4 of onion and mushroom mixture, and bun top.