Heat the oven to 425°F (220°C). Line a large rimmed sheet pan with parchment for easy cleanup.
Rinse the quinoa in a fine-mesh sieve under cool water for 20–30 seconds to remove bitterness.
Chop the vegetables into uniform pieces so they roast evenly.
Roast the vegetables: Add broccoli, bell pepper, zucchini, red onion, and cherry tomatoes to the sheet pan. Drizzle with 2 tbsp oil, season with 1/2 tsp salt and 1/4 tsp pepper, and toss to coat. Spread in an even layer. Roast 20–25 minutes, tossing once halfway, until edges are caramelized and tomatoes blister.
Cook the quinoa: While the veggies roast, combine rinsed quinoa, broth (or water), and 1/2 tsp salt in a medium saucepan. Bring to a boil, reduce to low, cover, and simmer 15 minutes. Remove from heat and let stand 5 minutes. Uncover and fluff with a fork.
Make the dressing: In a small jar or bowl, whisk lemon zest, lemon juice, olive oil, garlic, Dijon, honey/maple (if using), salt, and red pepper flakes until glossy.
Combine: In a large bowl, add fluffed quinoa and warm roasted vegetables. Pour over dressing and toss gently to coat.
Fold in herbs & extras: Add parsley and dill (or basil). Taste and adjust salt, lemon, and heat. Fold in chickpeas and/or feta if using.
Serve: Spoon into bowls. Finish with a squeeze of lemon and an extra sprinkle of herbs.