This is dry-frying, and only applies to whole spices. They are heated gently for 2-3 minutes in a heavy frying pan without any oil, shaken now and then, until the seeds start to change color. This has a beneficial effect, especially with certain spices such as cumin, for it draws out the flavor remarkably well. Most of the spices in commercial curry powders, and other mixtures such as garam masala, are treated in this way before being ground. In Indian cooking it is very important that the spices do not taste raw.
** Indian Recipes