In a medium bowl, whisk together all ingredients except beef.
Heavily slather the entire surface of the tenderloin (or roast) with the marinade then place it in a large zipper-topped plastic bag; pour any remaining marinade over the top.
Seal bag and refrigerate overnight or for at least 4 hours. At time of cooking, preheat outdoor grill to MEDIUM-HIGH. Remove beef from marinade (discarding marinade and bag); grill, uncovered, for 8 minutes per side.
Reduce heat to MEDIUM then cover and cook for 8 to 10 minutes or until desired level of doneness is achieved.