Prepare herb butter.
Mix softened butter, shallots, scallions, parsley, thyme, basil, oregano, marjoram, mustard, and Worcestershire sauce. Blend well. Roll into log using plastic wrap or parchment. Chill and reserve.
Place red peppers, onion, beef, green pepper in sequence. Repeat sequence until skewer is full. Finish end with a mushroom cap. Season brochettes with salt, pepper and soy sauce. Add garlic and cracked black pepper as well. Heat grill. Brush with oil. Soften a portion of the herb butter compound. Brush onto brochettes. Let sit for one hour. Place brochettes on grill. Baste with herb butter compound. Cook until meat is medium rare. Place on a serving platter.