In a bowl, mix the chicken with turmeric powder, black pepper powder, salt, and vinegar. Let it marinate for about 20-30 minutes.
Heat coconut oil in a pan. Add curry leaves, green chilies, and sliced onions. Sauté until the onions turn golden brown.
Add ginger-garlic paste to the onions and sauté for 2-3 minutes until the raw smell disappears.
Add the marinated chicken pieces to the pan. Stir well and cook for 5-7 minutes, allowing the chicken to sear and absorb the flavors.
Sprinkle garam masala and another black pepper powder. Stir to coat the chicken evenly with the spices.
Reduce the heat and add a little water. Cover and cook the chicken for 10-15 minutes until it is tender and cooked through.
Once the chicken is cooked, garnish with fresh coriander leaves and serve hot with rice or parathas.