Dunk the tomatoes in boiling water for 2 minutes, peel and roughly chop them.
Put lamb, chopped onions, olive oil, parsley and spices in a deep casserole on moderate heat and cook for 5-7 minutes. Throw in the tomatoes, cover and let it sweat for 10 minutes.
Now add the cooked chickpeas, 600 ml water, and salt. Cover and gently simmer for 20-30 minutes till the lamb is soft and the soup has amalgamated nicely.
Time to add the baby onions. Cook them for 15 mins more. Ladle steaming soup into bowls, top each with a slice of lemon and serve.