Wash beetroot thoroughly and peel it. Grate it using a medium grater or chop very finely. If you have a food processor you can use it.
Add coconut, garlic, green chili and cumin to a blender jar and blend it coarsely.
Heat a pan with oil and add mustard. When they begin to crackle, add curry leaves.
Saute for few seconds and add chopped onions. Fry until they turn pink or transparent.
Add grated beetroot. Sprinkle salt and begin to stir fry for 1 to 2 mins.
Cover and cook until tender on a low heat. If the beetroot is not tender, you may sprinkle little water and cook.
Add the coconut, garlic mixture and mix well. Saute for 2 mins on a medium to low flame. Taste test and adjust salt.
Serve beetroot thoran with steamed rice or chapati.