A thick, salty, oyster-flavored sauce called ho yau in Cantonese and mostly sold in bottles, sometimes in cans. Once opened store oyster sauce in the refrigerator.
Use in small amounts to add flavor to many dishes. It goes equally well with meats and vegetables. Originally it was made from oysters, salt and water and had a grey, unappealing appearance but processing techniques have improved the look and the flavor. Oyster sauce can be found in most well-stocked grocery stores although the best brands are found in Asian markets.