Ingredients

Makes 6 first-course servings

　　

For pastry

1 1/2 cups all-purpose flour

　　1/8 teaspoon salt

　　1/2 cup cold Plugrá (ultracreamy) butter or other unsalted butter, cut into bits

　　3 to 4 tablespoons San Pellegrino or tap water

　　

For filling

3/4 pound small red potatoes

　　1 cup heavy cream

　　1 large egg yolk

　　1/4 pound Maytag blue cheese, crumbled (3/4 cup)

　　1 1/2 teaspoons finely chopped fresh thyme

　　1 1/2 teaspoons finely chopped fresh rosemary

　　Fleur de sel or other coarse sea salt for sprinkling

　　

Special Equipment

a pastry or bench scraper; 6 (4-inch) tartlet pans

　　

Make pastry:

Step 1

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.

　　

Step 2

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.)

　　

Step 3

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:

Step 4

Put oven rack in middle position |and preheat oven to 350°F.

　　

Step 5

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.

　　

Step 6

Whisk together cream and yolk until combined.

　　

Step 7

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.

　　

Step 8

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.)

　　

Step 9

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.