I am a fan of puff pastry and I really enjoy stuffing it with all sorts of things and salmon is one of them. I halved this recipe as it is just me and my hubby and believe me, it was plenty, we could only eat one.
Preheat your oven to 425'F. Roll out each pastry sheet on a lightly floured surface to a 12 inch square.
Thaw the puff pastry for about 36 minutes. Cut each in half, forming four 12x6 inch rectangles.
Place one salmon fillet in the center of each of the rectangles, about 3 inches in from and parallel to one short edge.
Sprinkle each fillet with sea salt and fresh cracked black pepper and 1 tablespoon of shallots and 1 tablespoon of tarragon.
Brush edges of each rectangle with the egg glaze. Fold the long sides of pastry, enclosing the fillets. Seal the edges of the pastry. Place them seam side down on baking sheet. Brush with glaze.
Do not use tin foil, it will stick.
Bake the Wellingtons until the dough is golden brown, about 20 minutes. Remove from the oven and let stand for 10 more minutes.
Meanwhile make the sauce. Boil the wine, vinegar and 2 tbsp. of shallots in a heavy saucepan until the liquid is reduced to 6 tablespoons, about 8 minutes.
Remove the pan from the heat and add the butter, one piece at a time, whisking until each piece melts before adding the next. Whisk in 2 teaspoons of fresh chopped tarragon. Season with salt and pepper.
Cut into 3rds. Place sauce over pastry and serve hot.