Here the essential flavors of the Thai repertoire all come together: black pepper (prik thai), coriander roots, and garlic, salted with a little Thai fish sauce. Use this paste as a marinade for fish, grilled chicken (see Grilled Chicken with Hot and Sweet Dipping Sauce), or pork.Because the paste is so versatile, it’s handy to have a stash of coriander roots in the freezer. Whenever you have a bunch of coriander, after you have used the leaves, chop off the roots, wash, and store them in a plastic bag in the freezer. You don’t need to defrost them before using, as they can be chopped and pounded still frozen.