Preheat your oven to 425°F (220°C) and line two baking sheets with parchment paper.

Wash and chop your vegetables into uniform sizes: halve Brussels sprouts, cut sweet potatoes into 1-inch pieces, and slice the onion.

In a mixing bowl, combine broccoli, Brussels sprouts, sweet potatoes, onion, and chickpeas. Drizzle with olive oil and sprinkle with garlic powder, oregano, smoked paprika, cumin, salt, and pepper. Toss until evenly coated.

Spread the mixture in a single layer across the baking sheets, avoiding overcrowding.

Roast for 25-30 minutes, stirring halfway, until golden brown and tender.

Prepare the dressing by whisking tahini, maple syrup, Dijon mustard, lemon juice, and olive oil in a bowl. Gradually add warm water until smooth and pourable.

Assemble bowls by dividing the roasted mixture into bowls and topping with cherry tomatoes, Kalamata olives, feta cheese if using, and drizzle with tahini dressing. Finish with fresh parsley.