Preheat your oven to 400°F and line a baking sheet with parchment paper.
Toss the broccoli florets with 1 teaspoon of olive oil, salt, and pepper, then spread them in a single layer on the baking sheet.
Roast the broccoli for 15-20 minutes until the edges are slightly charred and tender.
While broccoli roasts, season the chicken breast with salt, pepper, and minced garlic.
Heat a grill or grill pan over medium-high heat and lightly coat with the remaining teaspoon of olive oil.
Grill the chicken for 5-7 minutes per side or until the internal temperature reaches 165°F, then let it rest for 5 minutes before slicing.
In a small bowl, whisk together the tahini, lemon juice, and 1-2 tablespoons of warm water until a smooth, pourable consistency is reached.
Assemble the bowl by placing the cooked quinoa at the base, followed by the roasted broccoli and sliced grilled chicken.
Drizzle the lemon tahini sauce over the top and serve immediately.