Preparation

Combine marinade sauce ingredients in large sauce pan, bring to a boil. Reduce heat and simmer for 30 minutes. Remove from heat. While sauce is cooking, cut beef into one inch cubes. Put meat into hot marinade sauce after removing it from heat. Stir to make sure all meat is well coated. Refrigerate for at least 4 hours. To prepare vegetables for skewers, cut onions into eighths and separate layers; core peppers and cut into eighths; drain mushrooms. Skewer meat alternating with vegetables and mushrooms. Cook on medium hot grill. Turn every 5 minutes and baste with marinade sauce. Grill 10 to 20 minutes (10 minutes for rare, 20 minutes for well done).