Add the lamb to a saucepan and cook over high heat. When browned remove from the heat and set aside.
Keep a tablespoon of fat in the saucepan but discard the rest.
Reduce to medium heat then add the garlic, onion and spinach. Cook until the onion is translucent and the spinach wilted; about 5 minutes.
Return the lamb to the saucepan with the onion-spinach mixture then add the tomato paste, cumin, harissa, chicken stock, chickpeas, lemon juice, salt and pepper. Simmer over low heat for about 20 minutes.
Add the pasta and cook for 15 minutes or until pasta is cooked.