e.  Cook on a high heat for five to ten minutes until it thickens. Add the frozen veg and (if using) lemon juice and cook for another five minutes.  Serve hot, over rice or noodles, or with bread to help soak up the sauce.  Cook on a high heat for five to ten minutes until it thickens. Add the frozen veg and (if using) lemon juice and cook for another five minutes. 