Keep the base sauce at a gentle simmer. Loosen the prepared spinach, separate the chicken pieces, finely chop the coriander stalks and roughly chop the leaves.

Heat the oil or ghee in a wide 3 litre pan over medium high heat. Add half the green chilli and the coriander stalks, followed by the Garlic and Ginger Paste. Stir continuously for 45 seconds without allowing the paste to brown.

Reduce the heat to medium. Add the Mixed Powder, cumin and Kashmiri chilli powder and stir for 20 seconds. Add the tomato purée and 30ml hot water, then cook for 60 to 90 seconds until the tomato darkens slightly and oil begins to show at the edges.

Add 200ml hot Curry House Base Sauce. Increase the heat and let it bubble steadily for 2 to 3 minutes, scraping caramelised sauce from the sides of the pan.

Add the remaining 200ml base sauce and the Curry House Pre-Cooked Chicken. Simmer for 4 to 5 minutes, stirring regularly, until every piece is steaming hot throughout.

Fold in the Curry House Pre-Cooked Spinach and simmer gently for 4 to 5 minutes, until hot and thick enough to coat the chicken. Add up to the remaining 20ml hot water only if the sauce becomes too thick.

Reduce the heat to low. Stir in the Garam Masala, lemon juice, three quarters of the coriander leaves and fine salt. Taste and adjust only if needed.

Remove the pan from the heat and rest for 2 minutes. Garnish with the remaining green chilli and coriander leaves before serving.