Preheat your oven to 400°F (200°C) and line a baking sheet with parchment paper.
Toss the broccoli florets with one teaspoon of olive oil and a pinch of sea salt, 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, season the chicken breast with dried oregano, sea salt, black pepper, and half of the lemon juice.
Heat a grill pan or outdoor grill over medium-high heat and lightly grease with a tiny bit of oil if needed.
Grill the chicken for 6-7 minutes per side, or until the internal temperature reaches 165°F.
Prepare the quinoa according to package instructions if not using pre-cooked, and fluff with a fork once ready.
In a small bowl, whisk the remaining teaspoon of olive oil and the rest of the lemon juice to create a light dressing.
Plate the grilled chicken alongside the quinoa and roasted broccoli, drizzling the lemon-oil dressing over the grains and vegetables before serving.