Finely chop the onion and garlic. Roughly chop the cauliflower, broccoli and carrot. Peel and chop the potatoes.
Heat the olive oil in a large saucepan. Add the onion and sauté for about 8 minutes until softened. Add the garlic and cumin seeds and stir for about 30 seconds.
Add the cauliflower, broccoli, carrot and potatoes. Pour in the vegetable stock and add the bay leaf.
Bring to the boil, then reduce the heat and simmer for about 20 minutes, or until the vegetables are tender.
Remove the bay leaf. Add the fresh coriander and blend the soup with a stick blender until lightly textured rather than completely smooth.
Stir in the drained chickpeas and simmer for a couple of minutes to heat through.
Season with salt and freshly ground black pepper to taste, then serve hot.