Although Beurre Blanc is one of the simplest sauces to prepare, the flavor is tangy and rich. Take care to add the butter bit by bit, stirring constantly with a whisk until each addition is completely incorporated.
Combine white wine, white wine vinegar, minced shallots, and black peppercorns in a small saucepan; bring to a boil. Cook until reduced to 2 tablespoons (about 4 1/2 minutes). Reduce heat to low. Add chilled butter, 2 pieces at a time, stirring with a whisk after each addition until butter is fully incorporated. Strain mixture through a fine sieve over a bowl; discard solids. Add salt and pepper.
Very good & easy. I used this full recipe on 1 lb. of sauteed red snapper