1/3 cup fresh lemon juice (from 2 lemons)
¼ cup finely chopped fresh oregano (or 1 Tbsp. dried)
2 Tbs olive oil, plus more for grates
coarse salt and freshly ground black pepper
8 boneless skinless breasts (about 6 ounces each)
4 medium lemons, halved crosswise
oregano sprigs for garnish (optional)
1. Prepare marinade: In a small bowl, whisk lemon zest and juice, oregano, oil, 2 tsp. coarse salt and 1 tsp. pepper. Divide marinade between 2 large re-sealable plastic bags. Place 2 chicken halves in each bag; shake to coat. Let marinate at room temperature for 30 minutes, turning bags occasionally.
2. Preheat grill to medium; lightly oil grates. Remove chicken from marinade, and pat dry with paper towels. Place chicken on grill. Cover and cook until lightly browned and cooked through, about 8-10 minutes. Turn chicken over, cover and cook until chicken is cooked through (an instant-read thermometer should read 175° when inserted into the thickest part of the chicken). If chicken is browning too quickly, move to cooler parts of grill or turn grill to low heat.
3. Transfer chicken to cutting board. Tent with foil; let rest 10 minutes. Meanwhile, place lemon halves on the grill, cut side down; cook until slightly charred, 8 to 10 minutes. Serve chicken breasts with grilled lemon halves. Garnish with fresh oregano sprigs, if desired.