Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
In a small glass bowl, whisk together the extra virgin olive oil, lemon juice, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken breast, broccoli florets, and sliced red bell peppers onto the prepared baking sheet in a single layer.
Drizzle the lemon-herb marinade over the chicken and vegetables, using your hands or a brush to ensure everything is evenly coated.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are tender with slightly charred edges.
Allow the chicken to rest for 5 minutes before slicing it into thin strips to maintain juiciness.
Assemble the bowl by placing the warm cooked quinoa at the base, followed by the roasted vegetables and sliced chicken.
Garnish with fresh avocado slices and an extra squeeze of lemon if desired before serving.