Spitzbuben (German Jam Cookies)

1 cup (2 sticks) unsalted butter, room temperature
2/3 cup granulated sugar
1 large egg
3 tablespoons pure vanilla extract
2 teaspoons salt
3 1/2 cups all-purpose flour
1/4 cup blackberry or other dark jam
1/4 cup confectioners' sugar

In a large bowl, beat together the butter and sugar until light and fluffy. Beat in the egg, vanilla extract and salt. Slowly add the flour, a little at a time, until fully incorporated. Dough will be very thick.

Form the dough into two balls, wrap each in plastic wrap and store in the freezer for about 30 minutes (if you must leave it longer than this, store it in the fridge instead).

Set the oven racks at the top and lower middle levels and preheat the oven to 400 degrees F. Directly on ungreased, uncovered cookie sheets, roll out some of the dough until it's about 1/4-inch thick. With a round cookie cutter, cut out as many cookies as you can, leaving about 1/2 inch of space between the cookies.

Bake cookies 3 to 4 minutes, then reverse the cookie sheets, putting the one from the upper middle rack on the bottom rack and vice versa. Bake another 3 to 4 minutes. Cookies are done when they're pale golden - do not let them brown. Remove cookies from oven and let them sit for a couple of minutes on the cookie sheets before transferring them to wire racks to cool completely.

Melt the jam over very low heat on the stove. Brush about 1/4 teaspoon of jam over half the cookies and top these with the plain cookies. Dust cookies with confectioners' sugar and allow cookies to sit for at least an hour before serving, so that the jam sets.

Makes about 2 dozen two-layer cookies.