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, then spread them on the baking sheet.
Roast the broccoli for 15-20 minutes until the edges are tender and slightly charred.
While the broccoli roasts, rinse the quinoa under cold water and place it in a small pot with 1/2 cup of water or vegetable broth.
Bring the quinoa to a boil, then reduce heat to low, cover, and simmer for 12-15 minutes until the liquid is absorbed.
Season the chicken breast with the remaining olive oil, lemon juice, salt, and pepper.
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, then serve alongside the fluffy quinoa and roasted broccoli.