Paruppu idli / Steamed rice and lentils cake

Paruppu idli or moonu (3) paruppu idli as often called, is made by steaming the batter consisting of fermented black lentils(urad dal) , split pigeon peas (toor dal) , split chick peas (bengal gram) and rice. 
Traditionally these idlis are made by pouring the batter into stainless steel tumblers/cups and steamed in pressure cooker(no weights reqd) for about 15 - 20 min, and once they are done will insert the knife to the edges of the tumblers then turn it upside down and you will get a nice tumbler shaped idlis. Goes well with spicy tomato chutney or Pudhina chutney. 

Ingredients
To soak and grind:

• idly rice - 3 cups
• urad dal / whole skinned  black lentils  -  1 cup
• toor dal / split pigeon peas - 3/4 cup
• bengal gram / split chick peas - 3/4 cup

For seasoning:

• mustard seeds - 2 tsp

• urad dal - 2 tsp
• cumin seeds - 2 tsp
• pepper - 2 tsp
• red chilly - 3
• green chillies - 3 ( add  more or less as per taste )
• curry leaves
• coconut - 1 cup
• oil - 1/4 cup

Method:  

1. Soak the ingredients in seperate bowls for 5-6 hours. (toor dal and bengal gram can be soaked together , where as rice and urad dal should be soaked seperately in different bowls.)
2. Drain the water and fine grind the urad dal until the mixture is frothy and set aside. ( prefer grinding it for atleast 15-20 min with 2 cups of water)
3. Grind the rice to a coarse mixture for about 10-15 minutes with 1 1/2 cups of water and set aside.
4.  And last grind the dals( toor dal & bengal gram)  to a coarse mixture for just 2-3 min and they are done. (no need to add water)
5. Now add all the ground mixture together and mix well with salt.
6. Set aside to ferment for about 8-12 hours or even overnight.
7. Heat oil in a wide pan, add mustard seeds. Once the seeds start to splutter then add urad dal, cumin seeds, pepper, red chillies, green chillies, curry leaves and grated coconut. 
8. Fry them all until golden color and add to the batter, mix well.
9. Grease the moulds on an Idli tray with cooking oil. Pour enough batter in each mould to fill it 3/4 full and steam for 15-20 min on a low medium flame.( to check if the idlis are cooked, just insert a tooth pick or fork, if comes out clean then its done.)
10. Now your paruppu idlis are ready to serve hot with any chutney of your taste. (Tip: take a teaspoon and apply little oil and go round the edges of the idlis on the tray and your idlis will come out ease without losing it shape).