Dry roast coriander, cumin, peppercorns, and methi seeds for 1 minute on slow flame. Cool and transfer to a grinder jar along with chopped garlic, green chilies, curry leaves, mint, coriander leaves, methi leaves, spinach, and ½ cup soaked tamarind water. Grind to a smooth paste.
Heat a wok or a saucepan on low flame and add 1 tablespoon ghee along with 1 tablespoon of cooking oil. Add marinated chicken pieces and stir fry on high heat for 1 minute. Reduce the flame to low, cover, and cook for 10 to 15 minutes. But make sure not to overcook it as the chicken will be later simmered in hariyali paste.
Heat another saucepan on low heat and add 1 tablespoon of ghee. Pour the hariyali paste from the grinder into the saucepan. Gently stir and simmer the paste on low flame for 5 minutes. You can cover the pan if it starts spluttering.
After 5 minutes, add 2 teaspoons of grated jaggery, ½ teaspoon salt, and all the cooked chicken pieces along with the gravy to the hariyali masala. Stir well and cook on slow flame for 5 more minutes.
Serve hot with roti, paratha, or naan.