Cut the chicken into small pieces and coat with the following marinade: 2 tablespoons of yogurt, a tablespoon of vegetable oil, a large clove of garlic, ginger and lemon. Then add salt, black pepper, mustard and chili.
Heat 2 tablespoons vegetable oil in a pan and sear the chicken on all sides.
In a pan, brown the chopped onion, the rest of the garlic and ginger, cook for 10 minutes, stirring so as not to stick.
Add the cumin, coriander, paprika, cinnamon, coating well. Pour 1 glass of water and let evaporate.
Add to this spicy paste, the crushed tomato and cashew nuts, 1 large glass of water, cover and simmer over low heat 20 min.
Then pass the spicy sauce in a blender to obtain a smooth sauce and put it back in the pan with the butter cut into pieces and the chicken.
The pieces will finish cooking in this sauce for 10 minutes.
Finally serve immediately with fresh rice.