I made this two weeks back for my in laws when I visited them. I learnt this from my MIL,I have made this so many times,every time this has come out successfully. It uses potato as ingredient and no urad flour. My MIL herself liked my murukku very much,which is the best credit for me. Do try yourself,sure this will come out great!
I have used the idiyappam flour which is very hand for me in various dishes.. The brand I buy is very fine powder in texture,so if you are trying with idiyappam flour make sure your flour is the fine in texture too.