Add tomato stock and increase heat to medium high and stir.
Add chopped chillies and crushed coriander.
Add prepared chicken. Raw poultry may be used or for a vegetarian option substitute with vegetables or paneer cheese.
Add cream and continue to simmer. Check seasoning and adjust if necessary.
Reduce to desired consistency over medium heat. Add remaining ten grams of chilled butter and stir to incorporate. Ideally sauce should be able to coat back of spoon.