Eel sauce, also known as unagi sauce or nitsume, is a sweet and savory sauce that is commonly used in Japanese cuisine as a glaze for grilled or broiled eel dishes such as unadon and unagi nigiri. Despite its name, it does not contain eel products and is vegetarian. The sauce is a thickened soy sauce with mirin and sugar, and sometimes dashi or sake is added for extra complexity. The primary ingredients in eel sauce are soy sauce, mirin, and sugar, and the sauce is simmered until it reduces and thickens to a syrup-like consistency with a glossy appearance. Eel sauce is easy to make at home with just a few ingredients, and it can be used as a dip or marinade for seafood, meat, chicken, and vegetables. Here is a basic recipe for eel sauce:

• 2 cups soy sauce
• 2 cups mirin
• 1 cup sugar

Simmer the ingredients on low to medium heat until the sauce thickens and becomes sticky.