In a small bowl, add the soy sauce, honey, vinegar, garlic powder, and ginger. Mix together thoroughly.
Stir in the onions.
In a dish for marinating steaks, pour in half of the sauce. Add the steaks. Cover and marinate in the fridge for at least 4 hours, flipping them halfway through. Do not go past 8 hours, since the acidity in the marinade will break down the meat.
Cooking The Steak Sauce
Grill the steaks until you have reached desired doneness.
Meanwhile, add the other half of the steak marinade to a small pot on the stove.
Bring to a low boil and simmer for 10 minutes.
Serve in a small dish and spoon over the meat as a sauce!