Wash and soak Kabuli channa / white channa for 6-8 hours (or overnight) in 2.5 cups water (500 ml).
Add salt, cardamom, cinnamon, cloves, gently keep tea bags (to get black colour for channa - optional) and pressure cook along with soaked water (final water level should be 1 inch above channa / chickpeas) for 30 minutes (reduce heat from high to medium after 3rd whistle and cook for 25 minutes). Allow to cool naturally. Open the lid and remove tea bags, cinnamon, cloves and cardamom. Reserve 1/2 cup (75 - 100 ml) stock for later use.
Dilute rice flour and 2 tbsp water in a small bowl or in a katori and make a smooth solution. Adding rice flour will make a thick and creamy gravy.
Dilute red chilli powder, coriander powder and turmeric powder in 2 tbsp water and keep aside (spice mixture).
Heat oil in a wide pan. Add onion and fry on medium heat until it becomes golden in colour.
Add ginger-garlic paste and stir well on low heat for 2-3 minutes until the raw smell goes.
Add diluted spice mixture and stir well for 2-3 minutes until the raw smell goes and it combines well with other ingredients.
Add boiled channa (along with the stock - maybe 1/2 cup), amchur powder / tamarind juice, diluted rice flour and salt to taste (if using amchur powder, add extra 50-75 ml water). Mix all the ingredients well.
Cover with a tight lid and cook on medium to low heat for 12-15 minutes until the gravy thickens.
Sprinkle chopped coriander leaves and decorate with onion rings / lemon wedges when serving with batura / puri / roti.