• Season both sides of the chicken breasts with salt and pepper to taste. 

For the Marinade

• Combine the olive oil, lemon zest, juice, garlic, rosemary, and thyme in a small measuring cup. Reserve ¼ cup of the marinade to baste while grilling.  Place the chicken, mushrooms, green onions and lemon slices in a glass dish, pour the lemon marinade over the chicken and veggies, turning to coat both sides. Cover the dish with plastic wrap and refrigerate for at least 20 minutes, or up to overnight.

Grilling

• Preheat the grill to a medium-high heat. Place the chicken breasts on the grill. (The veggies will be added during the last 10 minutes of cooking). Cook for 12 to 15 minutes, until the underside of the chicken breast is golden brown; baste as it grills. Turn the chicken breasts over, baste with reserved marinade, and continue to cook another 12 to 15 minutes, or until the chicken is thoroughly cooked to an internal temperature of 165℉.
• During the last 10 minutes of cooking, place the mushrooms, green onions and lemon halves on the grill, cut side down.