In a medium bowl, combine mustard, oils, yogurt, rosemary, garlic, shallot, lemon juice, vinegar, sugar, Worcestershire sauce, hot sauce, cayenne pepper, paprika and black pepper; whisk until well blended
Place cubed beef in a large re-sealable plastic bag and pour marinade over. Close the bag and massage the meat with marinade until well coated.
Transfer to the refrigerator for no more than 2 hours
Skewer the protein and veggies, starting with mushroom, red pepper, red onion, tomato, beef then red pepper, red onion, tomato, beef; repeat with mushroom and so on.
Brush the vegetables with the remaining marinade; discard the rest
Preheat the barbecue to 550-600ºF.
Place shish kebabs on hot grill and turn a 1/4 rotation every 2 1/2 minutes, closing the lid each time. Makes 4 skewers plus a meat skewer for extra beef.