Preheat your oven to 400°F (200°C).
Toss the broccoli florets with half of the olive oil, sea salt, and black pepper on a large baking sheet.
Roast the broccoli for 15-20 minutes until the edges are lightly charred and tender.
While the broccoli roasts, rinse the quinoa and combine it with 1/2 cup of water in a small pot.
Bring the quinoa to a boil, then reduce heat to low, cover, and simmer for 12-15 minutes until liquid is absorbed.
Season the chicken breast with salt, pepper, and the minced garlic.
Grill the chicken over medium-high heat for 6-7 minutes per side, or until the internal temperature reaches 165°F.
Let the chicken rest for 5 minutes before slicing into strips.
Fluff the quinoa with a fork and plate it alongside the roasted broccoli and sliced chicken.
Whisk the remaining olive oil with the lemon juice and drizzle over the entire dish before serving.