Preheat oven to 375 degrees F. Remove and reserve stems from mushrooms. Season mushroom caps with salt; set aside. Mince stems to yield 1/2 cup; discard remaining stems.
Combine ground beef, minced stems, blue cheese, bread crumbs, 3 tablespoons chives, and steak seasoning. Spoon beef mixture evenly into mushrooms.
Place stuffed mushrooms on rack in broiler pan. Bake in 375 degrees F oven 15 to 20 minutes. Sprinkle with additional chives, if desired.
1/2 pound ground beef
1/4 teaspoon salt
36 small button or cremini mushrooms (about 1-1/2 to 2-inch diameter)
1/3 cup crumbled blue cheese
1/4 cup soft whole wheat bread crumbs
3 tablespoons minced chives
1/2 teaspoon steak seasoning blend
Minced fresh chives (optional)