The secret to making less expensive cuts of meat tender is a good marinade. This one fits the bill. Mix up soy sauce, vegetable oil, ketchup, oregano, and three cloves of garlic, and then marinate the meat overnight. Grill, and slice on the diagonal.
This recipe was given to me many years ago by the county Extension service. I love the muffins' hearty taste and light texture. If you're cooking for one or two, they keep well in the refrigerator or the freezer.