Heat the oven to 190C (fan).
Separate the carrot tops from the roots.
Wash both thoroughly and set the tops aside for the chermoula.
Put the carrots (about 450g), whole or halved if thick, 650g new potatoes and two red or white onions (cut into wedges) on a large tin.
Drizzle with olive oil, cover with parchment and roast.
After 35 minutes, remove the parchment and cook for another 15–25 minutes, until charred and tender.
Mix in the lemon zest and juice (or the chopped preserved lemon), six lightly crushed garlic cloves and five teaspoons of ras el hanout (or your own blend) and roast for 10 more minutes.
Stir in any leftover carrot tops (roughly chopped), the chopped tomatoes and the undrained chickpeas and roast for a final 15 minutes, until hot and bubbling.
Meanwhile, make the chermoula: toast the cumin and coriander seeds in a dry pan, then grind to a powder.
Add the paprika, sea salt, garlic and diced red chilli, pound to a rough paste, then smash in 60g chopped carrot tops.
Mix in the lemon juice and zest and extra-virgin olive oil, then season to taste.
Dot spoonfuls of chermoula on the carrots in the tray, scatter over the crushed nuts and a few extra sprigs of carrot tops, and serve with couscous and yoghurt on the side.
