In small nonstick pan, sauté onion, thyme, parsley over low heat until onion is translucent. Add water if needed to prevent scorching. Combine ground chicken and onion mixture in medium bowl. Season with pepper, Worcestershire and pepper sauce. Shape chicken mixture into 4 patties. Grill or broil. Serve burger on bun with tomato slice and lettuce, with 2 tablespoon Mustard Sauce on the side.
Three mustard sauce
Sauté 1 1/2 tablespoon each diced onion and diced celery over low heat until onion is translucent. Add 1 tablespoon white wine, 1 tablespoon Dijon mustard, 1 tablespoon dry mustard and 1 tsp. green peppercorn mustard; mix well. Add 1/4 cup chicken stock and cook over medium heat for 2 minutes. Remove from heat, stir in 2 tsp. chopped parsley. Set aside to cool.