Preheat oven to
425°F. Roll out each pastry sheet on lightly
floured surface to 12-inch square. Cut each
in half, forming four 12x6-inch rectangles.
Place 1 salmon fillet in center of each rectangle,
about 3 inches in from and parallel to 1 short
edge. Sprinkle each fillet with salt, pepper,
1 tablespoon shallots and 1 tablespoon tarragon.
Brush edges of rectangles
with some glaze. Fold long sides of pastry over
fillets. Fold short edge of pastry over fillets
and roll up pastry, enclosing fillets. Seal
edges of pastry. Place pastries, seam side down,
on baking sheet. Brush with glaze.
Bake pastries until
dough is golden brown, about 20 minutes. Remove
from oven; let stand 10 minutes. Meanwhile,
boil wine, vinegar and 2 tablespoons shallots
in heavy small saucepan until liquid is reduced
to 6 tablespoons, about 8 minutes. Remove pan
from heat. Add butter 1 piece at a time, whisking
until melted before adding next piece. Whisk
in 2 teaspoons tarragon. Season sauce with salt
Cut pastries into
thirds. Place sauce and pastries on 4 plates.