Slice sirloin into 1.5" cubes. Mix all ingredients together in a large bowl or Ziploc bag; add beef, turn to coat and marinate for at least 4 hours, or up to 24 hours (better, but not necessary).

Prepare the rest of your kebab ingredients (suggestions: portobello mushrooms, bell peppers, onions, pineapple, cherry tomatoes, zucchini, squash, etc.) and if using wood skewers, soak in water (or beer!) for at least 30 minutes to keep them from burning on the grill.

Thread ingredients onto skewers and sprinkle with olive oil, garlic salt and pepper.

Grill over medium-high heat to desired doneness.