Preheat the oven to 180°C.
Cut the unpeeled onion into 4 wedges.
Peel and cut the beetroot and sweet potatoes into chunks. Scatter them into a baking tray. Tuck the unpeeled garlic cloves between them, then dust everything with the spices and drizzle them with the olive oil. Season with salt and pepper.
Bake for about 25 minutes, or until the veggies are tender.
Take the tray out of the oven and discard the skins of the onion, garlic and maybe red pepper..
Put all vegetable flesh into a saucepan and add the tinned tomatoes and the stock. Bring to the boil and cook for ten minutes.
Turn off the heat, add the parsley, then blend the soup with a stick blender until you get smooth, silky soup.
Drain the chickpeas and add them to the soup. Taste it, adjust the seasoning to your liking.
Reheat, then serve.