Take the split green gram lentils in a cooking pan or wok and dry roast them in medium flame with constant stirring. Ensure the lentils haven't changed color much. Next add the mint leaves, coriander leaves, little grated coconut and green chilly in to a mixer / blender and grind them together in to fine puree.
Next heat a pressure cooker adding oil, cumin seeds and curry leaves. When the cumin seeds begin changing color, throw in crushed black pepper. Saute and include mint leaves paste from above step and stir for few seconds.
Next add roasted moong dal and drained rice. Combine everything well.
Add 3 cups of water, salt and let it cook for about 3 whistles in medium flame. When the pressure subsides completely, mix and garnish with grated coconut.
Wonderful and colorful khara pongal with mint leaves is ready. Serve it hot.