I like all the recipes that I put up, of course, but this one ranks HIGH. I mean, some of them, no matter how good, I don't even remember that I have, but this is one we come back to again and again. I found it in one of those little grocery store check-out lane cook books: Best Recipes Coca-Cola Cool Recipes. There wasn't actually any Coke in it, but they really do go well together!
Combine beef broth, soy sauce, garlic, cumin, chili powder, and ground red pepper in resealable plastic food storage bag; knead bag to combine. Add beef and seal. Refrigerate up to 24 hours, turning occasionally.
Remove beef from marinade; discard remaining marinade. Grill beef over hot coals 7 minutes per side or until desired doneness. Grill bell peppers 7 to 10 minutes or until tender, turning once.
Slice beef and serve with bell peppers, tortillas, sour cream, and salsa.