Cut chicken into small pieces and squeeze half a lemon over it
Add 1 tsp turmeric powder and ½ tsp salt to chicken and mix well to marinate
Heat 5 tbsp vegetable oil and 50g butter in a pan on medium to low flame until melted
Add 2 chopped onions and cook for 2 to 3 minutes, stirring occasionally until onions start to caramelize and pick up color
Add 10 cloves chopped garlic and cook for 3 to 4 minutes until raw aromas disappear
Reduce heat to lowest setting and add 2 tsp Kashmiri red chili powder, 2 tbsp garam masala, 2 tbsp coriander powder, 1 tsp cracked black peppercorns, 1 tsp dry fenugreek leaves, and 2 tsp turmeric powder
Mix well and cook spices on very low flame for 30 to 40 seconds
Add 4 chopped tomatoes and salt, stir well
Cook tomatoes until softened and disintegrated into the sauce, about a few minutes
Add a splash of warm water and continue cooking until masala becomes thick
Add marinated chicken to the pan and stir well
Pan roast chicken on all sides to sear and lock in juices
Add a splash of warm water, cover the pan, and simmer on very low flame for 5 to 6 minutes
Uncover pan and cook for another 3 to 4 minutes, stirring occasionally
Once chicken is cooked and well coated with masala, add 2 mild green chillies, 3 tbsp chopped coriander leaves, 2 tbsp cold butter, and sliced ginger
Stir everything together and serve hot
