This is one of those ingredients that will be hard to replace if you are looking to cook authentic Indian cuisine. I did my research and it said that it is similar in flavor to sauteed leeks and fenugreek. It is actually a wheat starch and thickens your dish. I asked for help at the store too and it was good I did because I would have never been able to find this ingredient.
Where to get it in Philly: International House of Spices
Where to get it on the web: