Combine the soy sauce, garlic, brown sugar, pineapple juice and apple cider vinegar in a pot and bring it to a boil.
Immediately reduce heat and simmer over low heat for 3 minutes. Pour immediately into large baking pan or whatever you use for marinating your steaks.
Once it has totally cooled, add the steaks making sure they are generously covered; refrigerate a minimum of two hours.
Pull steaks back out and allow to rise to room temperature. Salt & pepper and grill as usual. Enjoy!