I had forgotten about this recipe. I don't do much grilling, but this one is a winner. It's been a while since I made it. I got the recipe from a friend years ago, when I was first married. For the meat tenderizer, I use the kind with Papain extract, not MSG. Durkee makes a good brand.
Make marinade: combine soy sauce, oil, molasses, ginger, dry mustard, and minced garlic cloves and mix well. Cut the steak into long strips about 1/4-inch thick. Sprinkle meat tenderizer on both sides of steak strips according to label directions. Add steak to marinade in a zip-top bag and let stand 15 minutes at room temperature.
Lace the steak strips accordian-style onto the skewers, with a pineapple chunk between each fold, using about 3 chunks of pineapple on each skewer. Grill over hot coals 5 to 7 minutes or to desired doneness. Turn frequently and baste with marinade while cooking.
If using wood or bamboo skewers, soak them for 30 minutes in water before preparing.