Preheat oven to 220°C fan.
Combine harissa, oil, cumin, salt in a large bowl. Add cauliflower, carrots, onion. Toss.
Add chickpeas. Toss again.
Spread on a large sheet pan. Roast 25 minutes, tossing once at 15 min, until vegetables are tender and chickpeas are crispy.
Serve with a dollop of yoghurt, fresh coriander, a squeeze of lemon.