1 3/4 cups all-purpose flour
1/2 cup confectioners' sugar
1 1/2 sticks (3/4 cup) cold unsalted butter, cut into bits
1 large egg yolk
2 tablespoons ice water
1/2 teaspoon light rum or vanilla
2/3 cup strained jam, such as apricot, raspberry, and strawberry

Into a bowl sift together the flour and the confectioners' sugar, add the butter, and blend the mixture until it resembles meal. In a small bowl whisk together the egg yolk, the ice water, and the rum, add the mixture to the flour mixture, and combine the mixture until it forms a dough. On a work surface knead the dough with the heel of a hand for a few seconds to distribute the fat evenly and form it into a ball. Dust the dough with flour and chill it, wrapped in wax paper, for 30 minutes.

Halve the dough, on a floured surface roll out 1 of the halves 1/8 inch thick, and cut it into rounds with a 1 1/2-inch scalloped cutter. Gather the scraps together, reroll them, and cut out more rounds. Roll out the remaining half of the dough 1/8 inch thick and cut out more rounds in the same manner. Cut out the centers of half the rounds with a 1/2-inch plain round cutter to form rings. Bake the rounds and rings in batches on greased baking sheets in the middle of a preheated 325°F. oven for 12 minutes, or until they are faintly golden. Transfer the cookies with a metal spatula to racks and let them cool.

Spread the bottom of each round lightly with some of the jam and top it with one of the rings. Drop a scant 1/4 teaspoon of the remaining jam in the center of each cookie and let the cookies stand on the racks for 1 hour.