3/4 lb unsalted butter, chilled
2 shallots, finely diced
1 tablespoon champagne or white wine vinegar
1/2 cup dry white wine
1/2 cup fish stock
8 to 10 teaspoons black caviar of your choice
Heat a tablespoon of the butter in a heavy bottom sauce pan over medium heat. Add the shallots and cook for several minutes until they become translucent and soft. Do not let them brown. Deglaze the pan with the vinegar and simmer until the liquid has almost evaporated. Add the wine and fish stock and reduce to about 3 tablespoons. Cut the remaining butter (still chilled) into pieces and add it, one piece at a time, into the pan. Stir or whisk the butter into the liquid until each piece is emulsified before adding the next piece. Continue stirring constantly until the sauce is thick enough to coat the back of a spoon. Add salt and pepper, to taste, and stir in 6 teaspoons of caviar. Keep warm.