Grilled Bok Choy

Ingredients
1 Medium head bok choy
1 1/2 Cup quartered button mushrooms
1 Small onion, cut into thin wedges
1/4 Cup chopped red bell pepper
1 Tbsp. vegetable oil
2 Tsp. peeled grated gingerroot
2 Tsp. soy sauce
1 Tsp. dark sesame oil (optional)
1 Serrano pepper, seeded and chopped
1 Clove garlic, minced
Directions
Coat grill rack with nonstick cooking spray. Preheat grill to medium-high direct heat. Cut bok choy leaves into 1 1/2-inch pieces; slice stems into 3/4-inch pieces. Combine all ingredients in large bowl; toss to coat. Place vegetable mixture toward one short end of 36x24-inch sheet heavy-duty foil. Fold one long side over to meet other long side and enclose vegetables. Fold and crimp ends loosely to enclose vegetables and leave room for expansion.
Place packet on grill. Grill, covered, 10 minutes (add 2 to 3 minutes for softer vegetables) or until vegetables are crisp-tender, turning once.