Preheat your grill or grill pan over medium-high heat.
In a small bowl, combine olive oil, lemon juice, minced garlic, salt, and pepper to create a marinade.
Place the chicken breast in a shallow dish and pour the marinade over it. Let it sit for at least 15 minutes for flavor infusion.
Meanwhile, preheat your oven to 425°F for roasting the broccoli.
Toss the broccoli florets with a splash of olive oil, minced garlic, salt, and pepper, then spread them evenly on a baking sheet.
Roast the broccoli in the oven for about 15-20 minutes until tender and slightly caramelized.
Grill the marinated chicken breast for about 6-7 minutes per side or until the internal temperature reaches 165°F.
Prepare the quinoa as per package instructions if not already cooked, typically bringing water to a boil, adding quinoa, reducing heat, and simmering for 15 minutes.
Plate the grilled chicken breast alongside the cooked quinoa and roasted broccoli. Enjoy your balanced and nutritious lunch!