Preheat the oven to 400°F or 200°C (180°C for fan ovens).
You will need 2 sheet pans or large baking sheets.
In a small bowl mix together the olive oil, harissa and the honey.
Spread the squash and sweet potato on one sheet pan.
Sprinkle with half of the cumin seeds.
Toss with half of the harissa mixture and put in the oven for 10 minutes.
Meanwhile, spread the chopped onions, red peppers and courgettes on the other sheet pan.
Sprinkle with half of the cumin seeds.
Toss with the remaining half of the harissa mixture.
When the 10 minutes are up, remove the sheet pan with the sweet potatoes from the oven and gently turn the mixture.
Return the pan to the oven, and also put the pan with the red peppers and courgettes in the oven as well.
Roast for about 15 minutes, turning the vegetables once half way through.
At this point the squash and sweet potato should be tender and the other vegetables should be just cooked.
The vegetables will have shrunk a little at this point so they will hopefully all fit on one sheet pan.
Add the drained chickpeas and stir to coat with some of the sauce.
Put back in the oven for 5 minutes to heat the chickpeas through.
Divide the couscous or rice (for a gluten free option) between four plates or bowls and serve the tagine over top.
Garnish with fresh or dried parsley.