This recipe comes from Copeland Marks' book Sephardic Cooking. He attributes the recipe to the Calcutta area of India. He says that almost all the women there knew how to make them and that they are a popular snack to be served with coffee or tea. The authentic version uses a home-made type of string cheese, but you can substitute the kashkaval, mozzarella or cheddar listed below. I have made these several times, with different cheeses and they are quite good. If you use kashkaval, I suggest French feta. If you use a less strongly flavored cheese, I suggest Bulgarian feta. I freeze them and keep them on hand for unexpected guests. You just thaw them for an hour on a cookie sheet and then reheat them at 350 degrees for 10 minutes. Prep and cooking time does not include one hour of refrigeration needed before assembling and baking.