Soak all the three paruppu (dal / lentils) for about an hour.
Drain the dal well and then grind it into a coarse paste with salt, red chilies, and asafetida.
Transfer the ground mixture into a greased steamer plate or in idli plates and steam it for about 10 -12 mins until the mixture appears cooked and glossy. When you touch the steamed mixture it will appear hard and it should not stick to your fingers.
Remove it and then break it into pieces and leave it aside to cool down.
In the meantime, clean the beans and chop it into tiny pieces. If the beans are very tender (like in my case), there is no need to cook them. We could directly add it when making the usilli and it would cook. If the beans are a little tough, then either steam it in the microwave until soft or cook it in boiling water.
Once the paruppu mixture has cooled down to room temperature, transfer it into a blender and grind it once to make it powdery.
Heat a wide pan and add oil to it. Add all the ingredients listed under seasoning and fry it for a minute.
Now add the beans to it and let it cook for 3-5 mins. This is only if you are using tender uncooked beans. If you have cooked your beans prior, then you do not have to cook it again. Add just enough salt needed for the beans and let it cook. (Remember that we ground the dal with salt).
Now add the steamed and powdered dal mixture to the cooked beans and give it a good mix. Let it further cook for about 5 minutes so all the flavors could come together.
Serve the Beans Paruppu Usilli with rice and Moar kuzhambu!