4 slices of ripe tomatoCooking on the range
In medium bowl stir together ground beef, ¼ teaspoon salt and pepper. Form into 8 large ¼ inch thick patties. In a small bowl stir together blue cheese, cream cheese and mustard.
Place about two tablespoons of cheese mixture on top of each of four patties. Top each with the four remaining patties. Press around the edges to seal. Place hamburgers in a 10 inch skillet.
Cook over medium heat, turning once, until desired doneness (12 to 15 minutes for medium). Place hamburgers on buns.
In same skillet with drippings place mushrooms and onions; add ¼ teaspoon salt and pepper and Worcestershire sauce.
Cook over medium high heat, stirring occasionally, until tender (4 to 5 minutes). Meanwhile place a tomato slice on each hamburger; top with grilled mushrooms and onions.
Using the microwave
Assemble as directed above. Place hamburgers on microwave-safe bacon/roasting rack or 12 X 8 inch baking dish.
Cover; microwave on high, turning hamburgers over and rearranging after half the time, until desired doneness (5 to 8 minutes for medium).