01 - Preheat oven to 425°F. Line a baking sheet with parchment paper.
02 - Toss broccoli florets and sliced red onion with olive oil, salt, and pepper. Spread on the baking sheet and roast for 20–25 minutes, stirring halfway, until golden and tender.
03 - Bring 2 cups water and 1/4 teaspoon salt to a boil in a saucepan. Add quinoa, reduce heat to low, cover, and simmer for 15 minutes. Remove from heat and let stand, covered, for 5 minutes. Fluff with a fork.
04 - Whisk together tahini, lemon juice, maple syrup (or honey), minced garlic, pinch of salt, and warm water in a small bowl. Add more water, a teaspoon at a time, until smooth and pourable.
05 - In a large bowl, combine the warm quinoa, roasted broccoli and onions, and half the almonds and parsley. Drizzle with the lemon-tahini dressing and toss gently to combine.
06 - Serve warm or at room temperature, topped with remaining almonds, parsley, lemon zest, and feta cheese if using.