Preheat your oven to 400°F and line a baking sheet with parchment paper.
Toss the broccoli florets with half of the olive oil and a pinch of salt and pepper.
Spread the broccoli on the baking sheet and roast for 15-20 minutes until the edges are crispy and charred.
While the broccoli roasts, rinse the quinoa under cold water and place in a pot with 1/2 cup of water.
Bring the quinoa to a boil, then reduce heat to low, cover, and simmer for 15 minutes until fluffy.
Season the chicken breast with lemon juice, minced garlic, salt, and pepper.
Heat a grill pan over medium-high heat with the remaining olive oil and cook the chicken for 6-7 minutes per side.
Once the chicken reaches an internal temperature of 165°F, remove it from the heat and let it rest for 5 minutes.
Slice the chicken and serve it alongside the quinoa and roasted broccoli.