Preheat your grill to medium-high heat and adjust your oven to 400°F for roasting the broccoli.
In a small bowl, whisk together olive oil, lemon juice, minced garlic, and a pinch of salt and pepper.
Coat the chicken breast evenly with the lemon-garlic marinade. Let it sit for at least 10 minutes to absorb the flavors.
Place the marinated chicken on the preheated grill. Grill each side for about 5-6 minutes or until the internal temperature reaches 165°F.
While the chicken is grilling, toss broccoli florets with a bit of olive oil, salt, and pepper, then spread them out on a baking sheet.
Roast the broccoli in the preheated oven for about 15-20 minutes until tender and slightly crispy edges form.
Prepare quinoa according to package instructions if not already cooked; typically simmer in water until fluffy.
To serve, plate a portion of quinoa, top with sliced grilled chicken breast, and add a generous serving of roasted broccoli. Drizzle any remaining lemon-garlic dressing over the top.
Enjoy your balanced, flavorful lunch!