Cut the tapioca into very thin pieces, add salt and boil in enough water till the tapioca pieces are done. Drain out the water and leave to cool a bit.
Grate the beetroot. Mix it with the boiled and cooled tapioca. Keep this aside.
Meanwhile, grind to a coarse paste: 3/4 cup shredded coconut, cumin seeds, fenugreek, 7 small onions, garlic, ginger and 2 green chillies.
Mix the coconut mixture with the beetroot and tapioca. Add salt as required.
Heat oil in a pan. Once hot, crackle the mustard seeds and fry the remaining shallots, dry red chillies, remaining 1/4 cup of grated coconut and curry leaves to a golden brown color.
Add turmeric and red chilly powder and stir in previously prepared tapioca mixture. Cover and wait till the veggies are cooked.
Tapioca and beetroot thoran is ready.
Tip: While boiling tapioca, add salt only when it is almost cooked. It should not be over cooked, otherwise the tapioca will get mushy.