Chicken Fajitas

This recipe comes from my friend Donna. She made these for us this past summer during our visit to their RI home. I cannot overstate this enough - these are AMAZING and totally worth the work! Serve with yellow spanish rice, shredded cheese, sour cream, salsa and anything else you like on fajitas.

1/3 c. lime juice (2-3 limes)
6 Tbsp. olive oil
3 medium cloves garlic, minced
1 Tbsp. Worcestershire sauce
1 1/2 tsp. brown sugar
1 jalapeño, seeds and ribs removed, chile minced
1 1/2 Tbsp. minced fresh cilantro leaves
2 tsp. salt
3/4 tsp. pepper
3 boneless, skinless chicken breasts (about 1 1/2 pounds), cut into big bite-size pieces
1 large red onion, peeled and cut into 1/2-inch-thick rounds (do not separate rings)
1 large red bell pepper, quartered, stemmed, and seeded
1 large yellow bell pepper, quartered, stemmed, and seeded
8 - 12 plain flour tortillas (6-inch)

In medium bowl, whisk together lime juice, 4 Tbsp. oil, garlic, Worcestershire, brown sugar, jalapeño, cilantro, 1 tsp. salt, and 3/4 tsp. pepper. Reserve 1/4 cup marinade in small bowl; set aside. Add another teaspoon salt to remaining marinade. Place chicken in marinade; cover with plastic wrap and refrigerate at least 15 minutes. Brush both sides of onion rounds and peppers with remaining 2 Tbsp. oil and season with salt and pepper. Remove chicken from marinade and place chicken smooth side down on hotter side of grill; discard remaining marinade. Place onion rounds and peppers (skin side down) on cooler side of grill. Cook chicken until well browned, 4 to 5 minutes; using tongs, flip chicken and continue grilling until chicken is no longer pink when cut into with paring knife or instant-read thermometer inserted into thickest part registers about 160 degrees, 4 to 5 minutes longer. Meanwhile, cook peppers until spottily charred and crisp-tender, 8 to 10 minutes, turning once or twice as needed; cook onions until tender and charred on both sides, 10 to 12 minutes, turning every 3 to 4 minutes. When chicken and vegetables are done, transfer to large plate; tent with foil to keep warm.

Working in 2 or 3 batches, place tortillas in single layer on cooler side of now-empty grill and cook until warm and lightly browned, about 20 seconds per side (do not grill too long or tortillas will become brittle). As tortillas are done, wrap in kitchen towel or large sheet of foil. Separate onions into rings and place in medium bowl; slice bell peppers lengthwise into 1/4-inch strips and place in bowl with onions. Slice chicken into 1/4-inch strips and toss with remaining marinade; arrange chicken and vegetables on large platter and serve with warmed tortillas.