Step 1

Heat gas or charcoal grill. Cut 12 (10x10-inch) sheets of heavy-duty foil. In 1-quart saucepan, melt butter over medium heat. Add onion; cook, stirring frequently, until onion is tender. Stir in 1/3 cup cilantro and the bell pepper; cook 3 minutes, stirring constantly. Stir in lime juice and garlic salt.

Step 2

Place frozen ear of corn in center of each sheet of foil. Drizzle butter mixture evenly over corn. Fold foil over corn so edges meet. Seal edges, making tight 1/2-inch fold; fold again.

Step 3

Place corn on grill over medium heat. Cover grill; cook 25 to 35 minutes, turning occasionally, until thoroughly heated. Cut large X across top of each packet; fold back foil. Sprinkle with 1 tablespoon cilantro.