Maytag Blue Cheese and Potato Tartlets

PreparationMake pastry: Blend together flour, salt, and butter with your fingertips or a pastry blender (or pulse in a food processor) just until mixture resembles coarse meal with some small (roughly pea-size) butter lumps. Drizzle evenly with 3 tablespoons water and gently stir with a fork (or pulse in processor) until incorporated. Squeeze a small handful of dough. If it doesn't hold together, add up to 1 tablespoon more water, stirring (or pulsing) until just incorporated, then test again. (Be careful not to overwork dough, or pastry will be tough.) Turn out dough onto a lightly floured surface and divide into 6 portions. With heel of your hand, smear each portion once or twice in a forward motion to help distribute fat. Gather dough portions together with scraper and press into a ball, then flatten into a 6-inch disk. Chill, wrapped in plastic wrap, until firm, at least 30 minutes. Fill and bake tartlets: Put oven rack in middle position |and preheat oven to 350°F. Cut potatoes into ¼-inch-thick slices and cover with cold water by 2 inches in a 1-quart saucepan. Simmer, uncovered, until tender, about 10 minutes. Drain and pat dry with paper towels. Whisk together cream and yolk until combined. Divide dough into 6 equal pieces. Roll out each piece into a 5-inch round with a floured rolling pin on a lightly floured surface, then fit each into a tartlet pan. Trim excess dough, leaving a 1/4-inch overhang, then fold overhang inward and press against side of pans to reinforce edge. Chill shells until pastry is firm, at least 10 minutes. Arrange about 4 potato slices, overlapping slightly, in each tart shell and crumble 2 tablespoons cheese into each. Divide cream mixture among tartlets, filling to 1/8 inch from top. Sprinkle each tartlet with 1/4 teaspoon each of thyme and rosemary and season lightly with fleur de sel. (If your sea salt is very coarse, lightly crush before sprinkling.) Bake tartlets on a baking sheet until bubbling and golden brown, 45 to 50 minutes. Cool in pans on a rack 10 minutes, then remove from pans and serve warm. Cooks' note:Pastry dough can be chilled up to 2 days.