COURTESY GOURMET MAGAZINE
1 1⁄3 cups all-purpose flour
White and colored sanding sugars
2⁄3 cup cornstarch
1 cup confectioners’ sugar (for filling)
1⁄4 teaspoon salt
1 tablespoon grated lemon zest (for filling)
2 sticks (1⁄2 pound) unsalted butter, softened
1 tablespoon fresh lemon juice (for filling)
1⁄2 cup confectioners’ sugar
2 tablespoons light corn syrup (for filling)
1 tablespoon grated lemon zest
1⁄2 stick (4 tablespoons) unsalted butter, softened (for filling)
1 teaspoon vanilla extract
MAKE COOKIES: Preheat oven to 350°F with rack in middle. Line 2 large baking sheets with parchment paper.
Whisk together flour, cornstarch, and salt.
Beat together butter and confectioners’ sugar with an electric mixer until pale and fluffy, then beat in zest and vanilla. At low speed, mix in flour mixture just until a soft dough forms.
Put sanding sugars in different bowls. Roll a scant teaspoon of dough into a ball and drop into sugar, turning to coat. Reshape if necessary and transfer to a baking sheet. Repeat, spacing balls 3⁄4 inch apart, until baking sheet is filled.
Bake until tops are slightly cracked but still pale (bottoms will be pale golden), 12 to 15 minutes. Transfer cookies on parchment to a rack to cool completely.
Form and bake more cookies on second baking sheet.
MAKE FILLING AND SANDWICH COOKIES: Beat together all filling ingredients in a large bowl with an electric mixer at medium speed until combined well. Transfer to sealable bag and snip off a corner.
Turn over half of cookies and pipe about 1⁄2 teaspoon filling on flat side of each. Sandwich with remaining cookies, pressing gently.
The sugared dough balls should be chilled for 30 minutes or frozen for 5 to 10 minutes to help preserve their round shape. Keep the sandwiched cookies chilled.
The unsandwiched cookies keep, in a metal cookie tin, at a cool room temperature for up to 4 days.