Peel off the beetroot using a peeler and chop it in to fine cubes.
Method
Cook the beetroot cubes in half cup of water in a pan. Add salt now. Let it cook in simmer till soft. Transfer it to a vessel and let it cool down.
Next, in a mixer take coconut, mustard seeds and red chilly together. Along with some water grind them together to fine paste. Whisk the curds in a bowl and keep it ready.
Add cooked beetroot cubes and ground coconut paste to the curds and combine well. Check and adjust salt.
Finally heat a tempering pan, add all the ingredients under the list "To temper". As the mustard seeds splutter and lentils turn brown, pour this tempering over pachadi. Simple curry is ready to serve with rice.
Note
Do not add too much water to cook the beetroot. It may turn the pachadi watery.
The consistency of pachadi should be thick, so it's better to use thick yogurt.
You can even replace red chilly by green chilly too.