1 lb. boneless beef chuck shoulder steak, cut 1 inch thick
1/4 c. chopped onion
2 tbsp. each chopped parsley and white vinegar
1 tbsp. vegetable oil
2 tsp. Dijon style mustard
1 clove garlic, minced
1/2 tsp. dried thyme leaves

Combine onion, parsley, vinegar, oil, mustard, garlic, and thyme. Place beef chuck should steak in plastic bag; add onion mixture, spreading evenly over both sides. Close bag securely; marinate in refrigerator 6 to 8 hours (or overnight, if desired), turning at least once. Pour off marinade; discard. Place steak on rack in broiler pan so surface of meat is 3 to 5 inches from heat source. Broil about 16 minutes, for rare and about 18 minutes, for medium, turning once. Carve steak diagonally across the grain into thin slices. Garnish as desired.