Linzer Cookies

In the bowl of a stand mixer fitted with the paddle attachment, beat butter and confectioners’ sugar at medium speed until light and fluffy, 2 to 3 minutes, stopping to scrape sides of bowl. Beat in egg and vanilla until well combined, stopping to scrape sides of bowl.

In a medium bowl, whisk together flours, salt, and nutmeg. With mixer on low speed, gradually add flour mixture to butter mixture, beating just until combined and stopping to scrape sides of bowl. Turn out onto a lightly floured surface, and divide dough in half (about 423 grams each). Shape each half into a disk, and wrap in plastic wrap. Refrigerate until firm, about 2 hours.

Preheat oven to 350°F (180°C). Line baking sheets with parchment paper.

On a lightly floured surface, roll half of dough to ¼-inch thickness. (Keep remaining dough refrigerated until ready to use.) Using a 2½-inch snowflake cutter, cut dough, and place 2 inches apart on prepared pans. Using a 1⅛-inch snowflake cutter, cut centers from half of cookies. Reroll scraps, and cut dough; place 2 inches apart on prepared pans.

Bake, one batch at a time, until edges are lightly golden, 10 to 12 minutes. (Let remaining cut-out dough stand at room temperature until ready to bake.) Let cool on pan for 5 minutes. Remove from pan, and let cool completely on wire racks. Repeat with remaining dough.

Dust cookies with cutouts with confectioners' sugar. Place Nutmeg Buttercream in a pastry bag fitted with a large round piping tip (Ateco #805). Pipe dollops of buttercream at base of each point on flat side of solid cookies. Spoon a scant 1 teaspoon (6 grams) preserves into center of all solid cookies. Place cookies with cutouts, flat side down, on top of preserves and buttercream. Refrigerate in an airtight container for up to 5 days.

In the bowl of a stand mixer fitted with the paddle attachment, beat butter and salt at medium speed until creamy, about 1 minute, stopping to scrape sides of bowl. With mixer on low speed, gradually add confectioners’ sugar alternately with milk, beginning and ending with confectioners’ sugar, beating just until combined after each addition. Beat in nutmeg and vanilla. Increase mixer speed to medium, and beat until light and fluffy, about 2 minutes, stopping to scrape sides of bowl. Use immediately.