Preheat oven to 375°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.
Cooking Tip: To make soft bread crumbs, place torn bread in food processor or blender container. Cover; pulse on and off, to form fine crumbs. One-half slice makes about 1/4 cup crumbs.
Place stuffed mushrooms on rack in broiler pan. Bake in 375°F oven 15 to 20 minutes. Sprinkle with additional chives, if desired.
Cooking Tip: Cooking times are for fresh or thoroughly thawed Ground Beef. Ground beef should be cooked to an internal temperature of 160ºF. Color is not a reliable indicator of ground beef doneness.
Nutrition information per serving, using 80% lean ground beef, per mushroom: 20 Calories; 9 Calories from fat; 1g Total Fat (1 g Saturated Fat; 0 g Monounsaturated Fat;) 5 mg Cholesterol; 49 mg Sodium; 1 g Total Carbohydrate; 0.1 g Dietary Fiber; 2 g Protein; 0.2 mg Iron; 0.8 mg NE Niacin; 0 mg Vitamin B6; 0.1 mcg Vitamin B12; 0.4 mg Zinc; 2.2 mcg Selenium; 5.9 mg Choline.