SMOKED SALMON BARQUETTES

Steps:

• Make dough:
• Blend together flour, butter, and salt in a bowl with your fingertips or a pastry blender (or pulse in a food processor) just until most of mixture resembles coarse meal with small (roughly pea-size) butter lumps. Drizzle evenly with 3 tablespoons ice water and gently stir with a fork (or pulse in processor) until incorporated.
• Squeeze a small handful: If it doesn't hold together, add remaining ice water, 1/2 tablespoon at a time, stirring (or pulsing) until just incorporated, then test again. (Do not overwork mixture, or pastry will be tough.)
• Turn out mixture onto a lightly floured surface and divide into 4 portions. With heel of your hand, smear each portion once or twice in a forward motion to help distribute fat. Gather dough together with scraper and divide into 2 pieces, then flatten each piece into a 4-inch square. Chill squares, wrapped in plastic wrap, until firm, at least 1 hour.
• Make barquette shells:
• Keeping remaining dough chilled, roll out 1 piece on a lightly floured surface into a 13-inch square. Arrange 12 barquette molds close together on a work surface and drape rolled-out dough over molds. Roll a lightly floured rolling pin over molds to cut dough, then lightly press into molds. Repeat with remaining dough, then prick each shell several times with a fork and chill all shells in a shallow baking pan until firm, about 30 minutes.
• Preheat oven to 375°F.
• Arrange barquette molds close together in shallow pan and cover with parchment. Put pie weights on top of parchment (over molds) and bake in middle of oven until edges of shells are pale golden,about 15 minutes. Carefully remove parchment and weights and bake shells until golden, 7 to 10 minutes more. Cool shells in molds on a rack 10 minutes, then remove from molds and cool completely.
• Prepare filling while shells bake and cool:
• Stir together onion, lemon juice, and a pinch of salt in a bowl and let stand at room temperature 30 minutes. Stir in salmon, sour cream, butter, zest, and pepper.
• Assemble barquettes:
• Fill each barquette shell with a scant teaspoon salmon mixture and top with a scant 1/4 teaspoon caviar.