Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Toss the broccoli florets with half of the olive oil, salt, and pepper, then spread them in a single layer on the baking sheet.
Roast the broccoli for 15-20 minutes until the edges are slightly charred and tender.
While the broccoli roasts, whisk together the remaining olive oil, lemon juice, and minced garlic in a small bowl.
Coat the chicken breast in the lemon-garlic mixture and season with a pinch of sea salt.
Grill the chicken over medium-high heat for about 6-7 minutes per side, or until the internal temperature reaches 165°F.
Let the chicken rest for 5 minutes before slicing it into strips.
Warm the pre-cooked quinoa if necessary and fluff it with a fork.
Assemble the bowl by placing the quinoa at the bottom, topped with the sliced grilled chicken and the roasted broccoli.