In a large Ziploc bag or a medium bowl, combine the olive oil, fresh lemon juice, minced garlic, dried oregano, dried thyme, 1/2 tsp salt, and 1/4 tsp black pepper. Whisk to combine.

Add the cubed chicken breast to the marinade, ensuring all pieces are well coated. Seal the bag or cover the bowl and refrigerate for at least 15 minutes, or up to 30 minutes while you prepare other components. (Do not marinate chicken with lemon juice for longer than 30 minutes, as it can start to 'cook' the chicken).

Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easier cleanup.

In a medium pot, combine the rinsed quinoa, 2 cups water or broth, and 1/4 tsp salt. Bring to a boil, then reduce heat to low, cover, and simmer for 15 minutes, or until all liquid is absorbed. Remove from heat and let stand, covered, for 5 minutes. Fluff with a fork.

While the quinoa cooks, toss the broccoli florets and bell pepper pieces with 2 tbsp olive oil, 1/2 tsp salt, and 1/4 tsp black pepper directly on the prepared baking sheet. Spread them in a single layer.

Remove the chicken from the marinade and arrange it in a single layer on one half of the baking sheet with the vegetables. Ensure chicken and vegetables are not overcrowded, as this will steam instead of roast. If necessary, use a second baking sheet.

Bake for 20-25 minutes, or until the chicken is cooked through (internal temperature reaches 165°F / 74°C) and the vegetables are tender-crisp and lightly browned, flipping halfway through.

Divide the cooked quinoa evenly among 4 meal prep containers. Add equal portions of the lemon garlic chicken and roasted vegetables to each container.

Garnish each bowl with chopped fresh parsley and a lemon wedge, if desired. Allow to cool completely before covering and refrigerating.