Thickened butter and flour with fish stock.
This is a type of basic sauce, also known as a mother sauce, that is created using a pale roux and a white stock. It is commonly referred to as a velouté sauce, which translates to “velvet” in English, due to its smooth and silky texture. This sauce is distinguished from béchamel in that it does not contain milk or cream. In English, it is sometimes referred to as “velvet” sauce due to its velvety texture.