Creating Grilled Lemon Herb Chicken with Roasted Mediterranean Vegetables and Quinoa is simple if you follow these steps:

1. Prepare Marinade: In a bowl, mix olive oil, lemon juice, lemon zest, minced garlic, rosemary, thyme, salt, and pepper to create the marinade.
2. Marinate Chicken: Place chicken breasts in a resealable bag or shallow dish. Pour the marinade over the chicken, ensuring even coverage. Seal or cover and refrigerate for 30 minutes.
3. Preheat Oven: While the chicken marinates, preheat your oven to 400°F (200°C) for the vegetables.
4. Prepare Vegetables: In a large mixing bowl, combine red bell pepper, yellow bell pepper, zucchini, red onion, and cherry tomatoes. Drizzle with olive oil, sprinkle with oregano, salt, and pepper, and toss to combine.
5. Roast Vegetables: Spread the vegetable mixture on a baking sheet. Roast in the preheated oven for 20-25 minutes, stirring halfway through, until tender and slightly caramelized.
6. Cook Quinoa: Rinse the quinoa under cold water. In a saucepan, heat olive oil over medium heat. Add quinoa and toast for 1-2 minutes. Add vegetable broth and salt, bringing it to a boil. Reduce heat to low, cover, and simmer for about 15 minutes or until all liquid is absorbed. Fluff with a fork.
7. Grill Chicken: Preheat a grill or grill pan over medium-high heat. Remove the chicken from the marinade, discarding the marinade. Grill chicken for 6-7 minutes on each side, or until fully cooked and no longer pink inside. Internal temperature should reach 165°F (75°C).
8. Slice Chicken: Once cooked, remove chicken from the grill and let it rest for 5 minutes before slicing.
9. Assemble Plates: On each plate, spoon a portion of quinoa, top with grilled chicken slices, and add a generous serving of roasted vegetables.