Soak the chana dal for 30 minutes. Add 1 1/2 cup water and pressure cook the dal with turmeric powder for 1-2 whistles or until soft. Drain and set aside.
Heat oil and add mustard seeds. When it pops, add ural dal, red chillies, hing and fry till the dal turns golden.
Now add green chilly, curry leaves and fry for a minute. Then add cooked dal, salt and mix well. Saute for 3-4 minutes.
Add the grated coconut and fry for a minute. Remove from heat and add lemon juice.
Notes
Make sure the dal is not over cooked and mushy. It should be firm to touch and soft.