Pre-heat your oven to 200C / 400F / gas mark 6.
Trim and peel the carrots, if they aren't all the same thickness, cut them in half length-ways or even quarters if they are particularly thick.
Thinly slice the onion then add to a roasting tin along with the prepared carrots and garlic cloves.
Drizzle the vegetables with olive oil and sprinkle with the sumac and salt then toss the vegetables in the oil and spices to ensure they are well covered.
Roast in the centre of the oven for 15-20 minutes or until they are just tender when poked with a fork.
Add the chickpeas to the roasting tin and roast for a further 5 - 10 minutes.
While the chickpeas are roasting, mix together the tahini and lemon juice in a bowl. Don't worry if adding the lemon juice makes the tahini seize up.
Slowly add cold water to the lemon and tahini mix and whisk until you have a sauce that can easily be drizzled.
Remove the roasting dish from the oven and serve with a drizzle of the lemon and tahini dressing followed by a drizzle of pomegranate molasses and a sprinkling of chopped parsley and lemon zest.