In an Indian grinder or Vitamix, grind together soaked and drained Toor Dal, Butternut Squash, Thai green chilies, and Salt. Sprinkle water as needed to grind a thick smooth batter.
Heat oil in a shallow heavy-bottomed pan (I use cast iron pans) to 350°F. (Another way to test if the oil is heated enough is to drop a pinch of batter into the oil. If the batter quickly rises to the top immediately, the oil is heated enough).
Start with dropping a tablespoon of batter into the oil and fry the vadai (fritter) till it crispy golden brown. Remove the vadai (fritter) from the oil with a slotted spoon and drain on paper towels. Taste and adjust for salt as needed before you fry the rest of the batter.
Deep-fry the rest of the batter similarily in batches. I was able to fry up seven fritters at a time.
Serve with chutney of your choice.