Cook the pasta according to the packet instructions. Reserve 100ml of the pasta water before draining. Cut the chicken into small pieces. Fry in the oil over medium-high heat until golden and cooked through. Add the onion and cook for 3–4 minutes, then add the garlic.
Add the tomatoes, tomato purée, and herbs, and simmer for 5 minutes.
Add the cream cheese and enough pasta water to create a lovely creamy sauce.
Add the spinach and stir until it wilts.
Mix in the pasta, season well, and finish with the grated cheese.