Step 1

Preheat gas grill for medium-high heat. Whisk together beer, Worcestershire sauce, cornstarch, garlic, mustard and pepper in medium bowl; set aside.

Step 2

Place five 18x12-inch pieces of heavy aluminum foil on counter. Spray each with cooking spray. Evenly place onion and potatoes on each piece of foil. Pierce bratwursts with fork and place on top of vegetables. Carefully fold edges of foil upward; pour about 1/4 cup beer mixture into each packet. Double fold top and ends of each piece of foil, leaving space for steam to gather.

Step 3

Place packets on grate; cover grill. Grill 20 to 25 minutes or until bratswurst is cooked through (160°F) and potatoes are tender. Carefully open packets. Serve with additional mustard and parsley, if desired.