My mom is an awesome cook. She used to make soft n crispy paruppu/dal vadai. Normally kadalai paruppu (Bengal gram) is only used for making paruppu vadai/aama vadai. But my mom use 4 different paruppu/dal, Which makes the vadai soft even after it cools down. Here is my mom's version of paruppu vadai.
Ingredients : Makes 6 Vadai's.
Urad Dal/Ulutham paruppu/Black gram - 2 Table Spoon
Moong Dal/Pasiparuppu/Green Gram - 2 Table Spoon
Channa Dal/Kadalai paruppu/Bengal Gram - 2 Table Spoon
Thuvar Dal/Thuvaram paruppu/Red Gram - 2 Table Spoon
Red Chilies - 4 Nos. (Adjust according to spice need)
Suji/Rava/Semolina - 1 Table Spoon
Hing/Perungayam(Asafoetida) - A Generous pinch.
Coriander Leaves - 2 Table Spoon
Ginger - 1 Table Spoon (Finely chopped)
Curry Leaves - Few.
Salt - As per needed
Cold Butter - 2 Table Spoon
Oil - To Deep fry
Soak Dal's / Paruppu together for 2 to 3 hours and drain it. Grind it coarsely along with ginger, red chilies, Salt.
Mix Suji/Semolina, chopped coriander leaves, asafoetida, cold butter and curry leaves to the ground mixture.
Heat oil in a deep pan, and take a small ball of mixture and flatten it in the palm and drop it in the hot oil (make sure oil is not fuming) and fry till both the sides turn golden brown, drop 3 or 4 vada's at a time, don't over crowd. Crispy and soft vadai's are ready to eat.