In a large bowl, whisk together 2 tablespoons of olive oil, minced garlic, lemon juice, lemon zest, oregano, salt, and pepper to create the marinade.

Add the chicken breasts to the marinade, turning to coat completely. Cover and refrigerate for at least 30 minutes or up to 4 hours for best flavor.

Cook the quinoa according to package instructions using water or chicken broth. Fluff with a fork when done and set aside.

Preheat the oven to 400°F (200°C).

Toss the broccoli, bell pepper, and zucchini with the remaining 1 tablespoon of olive oil, salt, and pepper. Spread on a baking sheet in a single layer and roast for 15-20 minutes until tender and slightly charred at the edges.

While vegetables are roasting, heat a large skillet over medium-high heat and add a light drizzle of oil. Remove chicken from marinade and reserve the marinade. Pat chicken dry, then cook for 6-7 minutes per side until internal temperature reaches 165°F and chicken has a golden crust.

Pour the reserved marinade into the skillet and bring to a rolling boil for at least 1 minute to ensure food safety. Continue cooking for 1-2 minutes total until the sauce reduces and thickens slightly.

Divide the quinoa among 4 meal prep containers. Slice the chicken and arrange on top of quinoa, then add roasted vegetables. Drizzle the cooked pan sauce over the chicken.

Garnish with fresh parsley before serving. Store in refrigerator for up to 4 days.