In a large bowl, whisk together lemon juice, oil,turmeric, garam masala, cumin powder,coriander powder, chilli powder, ginger& garlic paste. Add chicken and toss until fully coated. Let marinate for 1-2 hours. (preferable overnight)

In a large pot over the medium heat, melt 2 tablespoons butter. Working in batches, add chicken and cook until golden all over, about 2 minutes per side. Transfer to a plate.

Reduce heat to medium and melt 2 tablespoons butter. Add the dry chillies, Cashew nuts and diced onions.Cook until soft, about 5 minutes. Add 300ml water and cook until fragrant.

Once the onions cooked and water start to boil, take it off the heat. Drain all the water and blitz the onions and cashews nuts. Do not throw the water away. Keep it aside.

Heat up some butter.Add the dry spices (as listed above in the ingredients list), cumin powder, coriander and red chilli powder. Cook until fragrant. Add the onions and cashew purée and tomato purée into the dry spices. Stir it and return chicken to sauce with same water that cooked onions and cashews nuts. Add salt n 1/2tsp sugar. Let simmer until the chicken is cooked through, about 8 minutes.

Stir in double cream and remaining 2 tablespoons butter.

Garnish with coriander and serve warm over rice with naan or Roti.