1/4 Cup white or red wine vinegar
1/4 Cup dry white wine or vermouth
3 Tablespoons chopped shallots
3/4 pound chilled butter
salt and freshly ground pepper
The secret to success of Beurre Blanc is ‘chilled’ butter beaten over ‘very’ low heat
Reduce vinegar, wine, and shallots until liquid just films the bottom of the pan (about 1-2 Tablespoons. liquid). Cut chilled butter into Tablespoons.; keep chilled. When liquid has reduced, turn heat very low. Whisking constantly, slowly add butter – piece by piece. With each addition, the sauce will become creamy and thick, and a light golden color.
Season to taste with salt and pepper. Keep warm over water the same temperature as the sauce.
If you prefer to omit the white wine or vermouth, add an additional 1/4 Cup vinegar. For additional sauce, add more butter. To lighten sauce, add 1/4 – 1/3 Cup heavy cream at end.
Lemon Butter Sauce:
Replace vinegar and wine with an equal amount of lemon juice; omit shallots. Prepare as above. After the sauce is prepared, stir in finely grated lemon zest if you wish.