Vadai is a common south Indian appetizer/snack dish. You could classify it as a flour-based dumpling or a fritter( sorta!). The main ingredients in this dish are Urad dal and fresh methi leaves.
Urad Dal is also known as black gram dal and available commonly in any Indian store near you. Methi leaves(aka fenugreek leaves) although less common is available in some Indian stores as well. You could also use dried methi as a substitute. Like any other dried herb, the dired version is much more stong in flavor than the fresh leaves. Here is what they both look like :
4 indian green chillies, finely chopped ( I always include the seeds, you can remove them
1/2 cup cilantro, chopped
1/2 tsp of turmeric powder
1 1/2 tsp salt
Make sure the urad dal is washed well at least a couple of times before it is soaked. Add the soaked urad dal to a blender and with as little water as possible grind this into a thick batter. If you add too much water the vadai will be extra oily, or it will be so liquidy that you cannot drop it into oil. You must not be using more than 2 or 3 tablespoons of water. The final batter should look something like this: