Foamy Butter Sauce

• 1 ¾ sticks (200 g) softened butter
• 2 shallots
• 2</

At least three hours ahead of time, take the butter out of the refrigerator to soften at room temperature.

Peel the shallots and finely chop them on a cutting board.

A thick-bottomed saucepan that holds the heat is preferable for making this sauce.

Place the shallots and vinegar in a small heavy-bottomed saucepan and boil until the vinegar has evaporated and the shallots