If the rice is cold, reheat it in the microwave oven for a minute, covered. Transfer the rice to a large bowl and break up any lumps if necessary. If the rice is too hot, let it cool a little bit so the grains don't stick together.
Heat the oil in a thick bottomed frying pan. When the oil starts to heat up, add the mustard seeds and cover immediately. Wait for the seeds to pop, then lower the heat and add the urad dal. Wait for the urad dal to turn golden brown before adding the curry leaves, green chillies, cilantro, turmeric, and the roasted nuts.
Heat the oil in a thick bottomed frying pan. When the oil starts to heat up, add the mustard seeds and cover immediately. Wait for the seeds to pop, then lower the heat and add the urad dal. Wait for the urad dal to turn golden brown before adding the curry leaves, green chillies, cilantro, turmeric, and the roasted nuts. Stir once and turn off the heat. Spread this mixture on top of the cooked rice. Add salt to taste, and the lemon juice.
Toss gently until everything is evenly mixed. Adjust the salt and lemon juice at this point if needed. If the rice seems too dry, add a tsp of oil or ghee to the rice.
Garnish with fresh grated coconut and serve.