Sweet urad vada is crispy sweet bondas and prepared with whole urad dal, sugar and deep-fried.
1) First of all, fry the urad vada in medium heat only. If the oil is too hot the outer side becomes burned and the inside core will not be cooked.
2) At the same under hot oil makes bondas to drink oil.
3) Most importantly be careful while grinding the batter. Don't add water while grinding because the watery dough will not hold shape. If your batter becomes thin add a tbsp of rice flour, mix and proceed.