First of all cut the chicken into medium bite-size pieces. Marinate the chicken with the ingredients from the chicken marinade list. Mix well to coat the each chicken pieces evenly. Set aside and marinate for 15 minutes. ( If you have time, you can marinate for longer. )
In the meantime, finely chop the shallots, garlic cloves and coriander.
Heat the grill pan/skillet over medium-high heat, drizzle 1 tablespoon of oil and grill the marinated chicken pieces for 2-3 minutes or until charred. Then turn sides and cook for another 2-3 minutes. Remove from pan and set aside.
To cook the butter sauce, add 3 tablespoon of unsalted butter in the pan, fry the chopped shallots with medium heat until brown. Then add the garlic paste, onion paste and stir fry few seconds.
Follow with the tomato puree, turmeric, paprika, garam masala and salt to taste. Stir for few seconds.
Pour the water, cream and cashew nut paste in and cook for another 1-2 minutes.
Place the cooked chicken back in and stir well to combine with the sauce. Add more water if needed.
Close the lid and cook for another 2-3 minutes. Finish with the dried fenugreek leaves and chopped coriander.
Serve with cooked basmati rice, naan or flat bread. Enjoy!
Notes
How to make cashew nut paste: To make the cashew nut paste, soak about 2-3 tablespoons of cashew nuts in water for 30 minutes and drain the water. Place the cashew nuts in the blender/food processor, add 1-2 tablespoons of water, and blend it into a smooth paste. (Add more water if needed. )
Tomato Puree - Strained, skinned tomatoes, thick in consistency, also called tomato concentrate. It comes in tin, cans, or tubes. You can easily buy in most supermarket pasta or sauces aisle. If you are using Italian Passata or fresh tomato puree, the sauce will take more time to reduce. You can cook the sauce until it becomes thick and reduced by half to achieve the perfect curry sauce.
Double Cream ( Heavy Cream ) - can be substituted with coconut milk/cream or cashew nut cream.
Shallot onions- Suggest using them for curry dishes as they can be easily browned and melted in the sauces. ( Shallots will save lots of your time when blending the onions and cleaning the food processor. )