Bearnaise Sauce

What is it?

Butter and egg yolk form the base of this classic French-style sauce, with tarragon bringing the familiar herb note. It’s usually served warm with steak, fish, or vegetables, and the texture should be smooth and spoonable rather than thick like a gravy. In Sainsbury’s own range, it sits closer to the straightforward pantry sauces than to anything heavily seasoned or cream-based. The flavour profile is built around butter, vinegar or wine reduction, and tarragon, so it’s sharper and more aromatic than a plain butter sauce.