At Bellegarde Bakery in New Orleans, baker Graison Gill is part of a generation of renegade bakers who are eschewing industrially ground white flour in favor of grinding their own flours from crops like red Ruby Lee wheat and heirloom corn. “White flour is a corpse,” says Gill. “It’s a dead, shelf-stable product. Freshly stone-milled flour is a living ingredient, full of flavor, texture, aroma, nutrition, and nuance.” Buy Bellegarde Bakery’s stone-ground flour online at bellegardebakery.com. Lemon filling highlights the nuttiness of buckwheat flour in these shortbread cookie sandwiches from Nina Compton. Substituting store-bought buckwheat flour will yield a less nutty cookie. Be sure to store either flour in the freezer.
How to Make It
Stir together all-purpose flour, buckwheat flour, cornstarch, and 3/4 cup powdered sugar in a medium bowl. Combine granulated sugar, 1 cup butter, and 3/4 teaspoon salt in bowl of a stand mixer fitted with a paddle attachment; beat on medium-high speed until light and fluffy, about 2 minutes. Add egg yolk and 2 teaspoons vanilla; beat until combined, about 15 seconds, stopping to scrape down sides of bowl as needed. Gradually add flour-cornstarch mixture, beating on low speed until mixture just starts to clump together and flour is incorporated into dough, about 20 seconds.
Divide dough in half; shape each half into a 5- x 2-inch log (about 10 ounces). Wrap each log tightly in plastic wrap; chill at least 2 hours or up to 2 days.
Preheat oven to 350°F. Unwrap 1 dough log; slice crosswise into 18 (1/4-inch-thick) rounds. Arrange dough rounds 1 inch apart on a baking sheet lined with parchment paper. Bake in preheated oven until cookie edges are light golden, 10 to 12 minutes. Remove from oven; cool cookies on baking sheet 2 minutes. Transfer cookies to a wire rack to cool completely, about 30 minutes. Meanwhile, repeat process with remaining dough log.
Stir together lemon juice and 1 tablespoon water in a small bowl. Beat remaining 2 tablespoons butter with an electric mixer on medium speed until creamy, about 1 minute. Beat in remaining 1/4 teaspoon salt and remaining 1/2 teaspoon vanilla. Add remaining 3 cups powdered sugar to butter mixture, alternating with lemon juice mixture, beating on low speed until incorporated after each addition. Beat in remaining 1 tablespoon water, 1 teaspoon at a time, until consistency is thick but spreadable. Stir in lemon zest.
Transfer lemon frosting to a piping bag fitted with a 1/2-inch round tip. Turn 18 of the cooled cookies upside down; pipe bottoms of cookies evenly with frosting (about 1 tablespoon per cookie). Top with remaining 18 cookies (right side up), creating 18 cookie sandwiches total.