To make ulundu or urad dal filling:
1/2 cup urad dal
2 tablespoon channa dal
4 green chilies or to taste
1/2 teaspoon salt or to taste
1 tablespoon sesame oil (til oil or nala ennai)
1/2 teaspoon mustard seeds
a pinch of asafoetida
a few curry leaves
Wash and soak the dals for at least one hour. After it has been soaked add some green chilies to taste and some salt and grind it to a smooth paste with very little water. Pour the ground mass into a steamer tray and steam it for 20 minutes or so until the mass is cooked. When a knife is inserted into the mass comes out clean it is cooked. Let the urad dal mass cool after which cut it into small bits.
Next, heat a pan with 1 tablespoon of oil add mustard seeds to it.
When the mustard seeds pop add a pinch of asafoetida and the curry leaves and let it sizzle for few seconds next add the urad dal mass and mix everything and let it cool. When it is cool divide it into 10 parts shaped into oval or oblong.
To Make Rice Flour covering:
1 cup rice flour
1 1/4 cup water
2 teaspoon sesame oil( til oil or nala ennai)
1/4 teaspoon salt to taste.
Heat the water on medium heat with salt and sesame oil, when the water starts boiling add the rice flour and immediately start mixing and kneading the dough for at least 5 minutes until all of the lumps are removed and a smooth dough is formed. Cover and let it cool, after which divide it into 10 parts.
To assemble the kozhukattai take one of the divided rice flour dough flatten it to a disc shape put the urad dal filling in the center and cover it by bringing the edge of the disc over to cover it. Pinch the edges to seal it. Making it look like a crescent shape. Do the same with rest of the dough and filling.
Steam the assembled kozhukattai for 8 to 10 minutes or until it is done.