4 sheets frozen puff pastry, thawedFlour8 6-ounce skinless salmon filletsKosher salt and freshly ground Black pepper to taste2 tablespoons minced shallots2 tablespoons chopped fresh tarragon1 tablespoon chopped fresh dill3 eggs, beaten½ cup dry white wine1/3 cup rice wine vinegar½ cup heavy cream½ tablespoon minced shallots½ cup chilled butter, dicedPreheat oven to 425 degrees. Roll out each pastry sheet on a lightly floured surface to 12-inch squares. Cut each in half, and half again, to make 8 rectangles.Put a salmon fillet in the center of each rectangle. Sprinkle with salt, pepper, a bit of shallot, tarragon and dill. Brush edges with the egg. Fold up to enclose the fillet and seal the edges. Place on baking sheet, seam side down.Brush pastries with beaten egg (for glaze) and bake until the dough is golden brown, about 20 minutes. (Mine were a bit larger and took about 28 minutes.) Remove from the oven and let stand 10 minutes.Meanwhile, boil the wine, vinegar, cream and remaining shallots in a heavy saucepan until reduced to about a third of a cup. Remove pan from heat.Add butter a piece at a time, whisking until melted before adding the next piece. Whisk in remaining tarragon. Season with salt and pepper.Cut pastries into thirds. Spoon sauce over and serve.Serves 8.