In a separate pan, heat oil, add mustard, cumin, curry leaves and red chilies. Let the seeds splutter and chilies change color.
Add crushed garlic and fry until light golden brown.
Add chili powder, turmeric and give a quick stir.
Pour the tempering over dal, keeping aside a spoonful for garnish. Cover and let the dal simmer for few minutes. Give a good stir, simmer for few minutes if the dal is too thin.
Turn off the heat, transfer to a serving bowl and garnish with cilantro and remaining tempering.