Finely chop the onion, garlic, ginger and turmeric. Chop the carrots and tomatoes.
Heat the olive oil in a large saucepan over a medium heat. Cook the onion for about 5 minutes until softened.
Add the garlic, ginger and turmeric, then cook for another minute until fragrant.
Stir in the carrots and garam masala, coating the vegetables well in the spices.
Add the chopped tomatoes and cook for 30 seconds before pouring in the vegetable stock.
Bring to the boil, then reduce the heat and simmer for about 20 minutes, or until the carrots are tender.
Remove the pan from the heat. Add half of the chickpeas and the coriander leaves, then blend with a stick blender until smooth or slightly rustic, depending on your preference.
Stir in the remaining chickpeas. If the soup is thicker than you like, add a little extra stock or water.
Reheat gently if needed, then taste and adjust the seasoning.
Serve hot, sprinkled with black cumin (nigella) seeds.