Reheat bacon according to package directions until crisp; coarsely crumble. Sauté onion in butter in a large skillet over medium heat 5 minutes until beginning to brown. Stir in garlic, mushrooms, and 3/4 tsp. salt. Sauté 10 minutes or until mushrooms are tender and liquid evaporates. Stir in bacon, parsley, and 1/8 tsp. pepper.
While mushrooms cook, sprinkle both sides of steaks with remaining 1 tsp. salt and 1/2 tsp. pepper.
Broil 5 1/2" from heat 7 minutes on each side or until desired degree of doneness. Let stand 5 minutes before slicing. Cut steaks into thin slices; arrange on a serving platter, and top with mushrooms.