Here is a ulunthu vadai I made in paniyaram pan (puff pancake pan). (Click to see my paniyaram pan). It is not a complete diet vadai, but can be made with lesser oil than deep frying. When comparing the taste, I find this one pretty much similar to the ulunthu vadai.
Ingredients: (For 21 small vadai)
Urid dhal - 1 cup (200 gm)
Oil (corn oil / canola) - 6 tbsp
Shallot / red onion (chopped) - 1/2 cup
green chilly - 2 (finely chopped)
cumin - 1/4 tsp
whole black pepper - 1 tbsp + 1 tsp
curry leaf - 1 sprig
Ginger - 1 tsp (finely chopped)
Wash the urid dhal twice thoroughly. Soak the urid dhal in cold water
for 2 hours. Grind it to a fine paste with very little water. The
final consistency should be like softened butter.
Add the required salt + 1 tsp black pepper and grind again for a while.
Pour the batter to a mixing bowl. Taste and adjust the salt now.
Mix the finely chopped onion, green chilly, curry leaf , whole pepper, cumin with the batter.
Heat the paniyaram pan with 1.5 tsp oil in every hole. Wait till it reaches the hottest point. Reduce the flame to lowest. Fill each hole with the vadai batter upto 3/4 th height.
Put a tight lid and wait to hear a dripping sound by steam.
Using a skewer, flip the vadai and cook for few seconds.
Take out, drain the oil in paper towels.
(From the second batch we may need very lesser oil in each hole).
Ulunthu vadai without frying is ready!
Serve with coconut chutney along with hot coffee or tea in the evening.
Also makes a good side dish with Idly, Venn pongal, sarkarai pongal etc.