Beef Fajitas

Combine olive oil, jalapeño brine, lime juice, soy sauce, Worcestershire sauce, sugar, cumin, garlic, and 1/2 teaspoon each of the salt and black pepper in a bowl; mix well with a whisk or fork.

Place beef in a baking dish or container. Pour 3/4 of the marinade over beef, making sure beef is covered on all sides.

Cover with plastic wrap, and chill at least 1 hour and up to 24 hours. Reserve remaining 1/4 of the marinade in a small container with a lid, and chill until ready to cook vegetables.

Preheat grill to medium-high. Remove beef from marinade; discard marinade. Grill beef until desired doneness, 3 to 4 minutes per side for medium. Remove beef to a cutting board; cover with foil, and let stand 10 minutes.

Brush bell pepper rings, onion rings, and jalapeño chiles with reserved 1/4 of marinade, and sprinkle with remaining 1/2 teaspoon each salt and black pepper. Grill until soft and lightly charred, 2 to 3 minutes per side. Place bell peppers, onions, and jalapeños on a large platter.

Slice beef across the grain, and serve on top of vegetables. Serve with tortillas, guacamole, and salsa, if desired.