Whisk together the lemon juice, one teaspoon of olive oil, and a pinch of salt and pepper in a small bowl to create a marinade.
Place the chicken breast in the marinade and let it sit for at least 15 minutes to absorb the flavors.
Preheat your oven to 400°F and line a baking sheet with parchment paper.
Toss the broccoli florets with the remaining teaspoon of olive oil and the minced garlic, then spread them evenly on the baking sheet.
Roast the broccoli for 15 to 20 minutes until the edges are slightly browned and tender.
While the broccoli roasts, heat a grill pan or outdoor grill over medium-high heat.
Grill the chicken breast for 6 to 7 minutes per side or until the internal temperature reaches 165°F.
Warm the pre-cooked quinoa in a small saucepan or microwave until heated through.
Slice the chicken and serve it alongside the quinoa and roasted broccoli for a balanced and clean lunch.