In a bowl, add the chicken, white pepper, curd/yoghurt, and salt, mix well ensuring the chicken pieces are well coated with the marinade and keep them aside for 30 minutes to 1 hour.
Heat oil in a pan over medium heat. Add the chopped onion, green chilli and cashews and saute until they turn translucent.
Cool and grind them to a fine paste in a blender/food processor.
In the same pan, heat oil add the ginger-garlic paste and saute until the raw smell disappears.
Add the ground paste and saute until the oil separates. Once the oil is separated, add the marinated chicken and mix. If the gravy is too thick, you can add a little water to achieve your desired consistency.
Add the spice powders (coriander powder, garam masala, cumin powder) and mix. Cook the chicken on medium heat until it's cooked through and the oil starts to separate from the masala. Stir occasionally to prevent sticking.
Once the chicken is cooked, check for seasoning and adjust if necessary.
Lower the heat, add the fresh cream and let it simmer for another 2-4 minutes.
Garnish with the crushed kasuri methi (dried fenugreek leaves) and a blob of butter while serving.
Serve Malai chicken hot with naan, roti, appam or rice.