Take a heavy-bottomed pot, add the unwashed moong dal and dry roast it over medium-high flame. You need to cook it while stirring continuously, for 3-4 minutes or until the colour of the dal changes from yellow to light brown/mustard (check the above picture) and it starts giving out a nutty aroma. Transfer it to a bowl and immediately rinse it with water. Keep it aside.
Pour rice into the same pot and dry roast it for 2-3minutes. Keep stirring until its colour changes to pale brown colour (check the above picture). Transfer it to a bowl and rinse it with water. Keep it aside.
Wipe the same pan with a cloth or kitchen towel. Pour mustard oil and heat it over medium flame until it starts to smoke. Then add dried red chillies and cumin. Let the seeds splutter. After that lower the flame and add hing. Mix well and cook for few a seconds.
Add tomato, ginger and salt. Mix well and cook over low flame for a few minutes until the tomato softens.
Add sugar, turmeric powder and coriander powder. Stir it and cook for 2-3 minutes.
Then add the washed rice and dal. Give it a good mix.
Pour water and mix well. You may require 3-4 cups of water. Start with 3 cups and you can add more if the khichdi starts drying out while the rice and dal are not cooked completely. Here I have used 3.5 cups of water.
Add green chillies and increase the flame to high. Let it boil for a few minutes until the rice and dal are cooked through.
Turn the flame off. Add crushed green cardamom, cinnamon, cloves and pour ghee over the top. Mix well. Serve hot.