Step 1: Heat the oil in a large pot. Add the onion and cook until translucent.

Step 2: Drain the soaked chickpeas and add them to the pot together with the vegetable stock. Bring to the boil, then reduce the heat and cover. Simmer for 30 minutes.

Step 3: In the meantime toast the cumin in a small ungreased frying pan, then grind them in a mortar. Add the garlic and salt and pound to a fine paste.

Step 4: Add the paste and the harissa to the soup and simmer until the chickpeas are tender, about 30 minutes.

Step 5: Season to taste with salt, pepper and lemon juice and serve hot.