In a large resealable bag, combine the soy sauce, olive oil, water, molasses, mustard powder, ginger, garlic powder and onion powder. Seal and shake the bag to mix together. Add steak strips to the bag and seal. Refrigerate for at least 8 hours to marinate.
Preheat the oven's broiler. Thread meat onto skewers and place on a broiling rack.
Broil the steak for 3 to 4 minutes on each side. Arrange on a platter to serve.