Soak rice and urad dal separately for 3 to 4 hours.
Grind the dal and rice smoothly by adding water. The batter should be thick like urad dal vada batter.
Add the salt and allow this batter to ferment for a minimum of 2 hours. We usually grind it the day before and let it ferment overnight. (see notes if you can't ferment the batter)
Steps: Tempering and Frying:
Chop the green chilies and ginger finely.
Heat 2 tsp oil for tempering.
When the oil is hot, add the mustard seeds, pepper, green chilies, curry leaves, and ginger.
When the mustard seeds start to splutter, then add this tempering to the batter.
Also, add the grated coconut and cilantro if using to the batter and mix well. The vellai appam batter is now ready.
Now heat the oil for frying.
Use a deep rounded spatula or spoon and scoop out the batter and pour it carefully in the oil.
Fry it over medium flame until the appam turns golden brown. I usually fry two to three vellai appams in one batch.
Drain it on a tissue paper to remove the excess oil.
Similarly, make /Fry vellai appams with the remaining batter.
That's it vellai appam is ready.
Serve this hot with your favorite chutney.
Notes
Black pepper adds a unique flavor so try not to skip. Adjust the green chilies, ginger, and salt according to your preference.
If time is pressing and if you are not able to ferment the batter then add approximately 1 tbsp of sour yogurt and make these appams.
Always fry over medium heat and do not crowd the frying pan with too many appams. Fry three to four at the maximum.