Hoisin sauce is a thick, dark sauce commonly used in Chinese cuisine. It is made from fermented soybeans, sugar, vinegar, garlic, and various spices, giving it a sweet and savory flavor. Often used as a dipping sauce or marinade, it adds depth to dishes like Peking duck and stir-fries. This versatile sauce can also be used in Vietnamese dishes, such as pho or as a glaze for meats. Its unique taste makes it a popular condiment in many Asian restaurants and households, enhancing the flavor of both savory and sweet dishes.