Melt margarine in a saucepan. Add onions and fry gently for 5 minutes or until soft.
Add turmeric, ginger, curry powder, salt and flour, then stir in stock and tomatoes. Add jam and bay leaf, bring to the boil and simmer for 30 minutes. Remove from heat, stir in lemon juice and leave overnight.
Next day add cooked chicken to the sauce. Stir in cream and reheat. Serve over rice, garnished with lemon slices and parsley.
You don't have to necessarily use a whole jointed chicken for this dish. If you have a preference, use just thighs, for example, or use a combination of bone-in thighs and drumsticks with boneless breasts.