Season salmon fillets with salt and pepper. Place a steaming rack in a saucepan or pot and fill with a couple of inches of water. Cover and let salmon steam until the fish flakes. Then set aside to cool.
Begin the lobster bisque sauce. Melt the butter over medium heat in a saucepan, add the shallot saute and saute until translucent. Whisk in the flour to make a roux. Add the brandy and gradually whisk in the stock. Let reduce by half. Whisk in heavy cream and remove from heat.
While the lobster bisque sauce is reducing, make the vol-au-vent.
Preheat oven to 375 degrees F.
Roll out puff pastry dough, and using a 4-inch circle or biscuit cutter, cut out 8 dough rounds. Place 4 of the dough rounds on a lightly greased baking sheet. Using a 3 inch circle or biscuit cutter, cut a concentric circle in the middle of the remaining 4 inch dough rounds to create a half-inch wide circle of dough. These half-inch wide circles of dough are to be used without the 3- inch pieces from the center. Place 1 of these half-inch wide circles of dough on top of each of the rounds already on the baking sheet, matching up the edges. Brush egg wash over the surface of each of the paired dough circles and rounds. Then use a fork to prick through the dough around the perimeter (that is, through each dough circle and into the accompanying round beneath it). Place in the oven and bake until golden brown, about 6 to 8 minutes. The center of each will rise. Remove pastry shells from oven and allow to cool slightly.
Flake the now cooled salmon into chunks and fold sauce into the salmon. (Do not feel compelled to use all of the sauce. The filling should not be too liquid.) Spoon some into each of the pastry shells. Sprinkle with fresh dill and top with 1/4 teaspoon caviar.
Recipe courtesy of Robert Irvine with Brian O'Reilly Harper Collins Publishers, copyright 2007.