You can bake the cookies and make the filling a day ahead.

　　

Ingredients

makes 15 sandwich cookies

　　Grated zest of 1 ruby red grapefruit, plus 1/4 cup freshly squeezed juice

　　1 cup sugar

　　1 cup all-purpose flour, plus more for dusting

　　3/4 cup cake flour (not self-rising)

　　1 teaspoon baking powder

　　1/2 teaspoon salt

　　1 stick (1/2 cup) unsalted butter, room temperature

　　2 large egg yolks

　　Grapefruit Cream Filling (recipe follows)

　　

Grapefruit Cream Filling

1 stick (1/2 cup) unsalted butter, room temperature

　　2 cups confectioners’ sugar

　　1 tablespoon honey

　　3 tablespoons freshly squeezed ruby red grapefruit juice

　　(makes enough to fill 15 sandwich cookies)

　　

Step 1

Preheat the oven to 350°F. Line a large baking sheet with parchment paper; set aside. In a small bowl, combine the grapefruit zest with 1 tablespoon sugar; set aside. In a medium bowl, whisk together both flours, baking powder, and salt; set aside. In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and remaining sugar on medium-high speed until light and fluffy, about 2 minutes, scraping down the sides of the bowl as needed. Add the egg yolks, and beat until combined, scraping down the sides of the bowl as needed. Beat in the reserved zest-sugar mixture. Add flour mixture in two batches, alternating with the juice, and beat to combine.

　　

Step 2

Turn out the dough onto a piece of plastic wrap, and shape into a 1-inch-thick disk. Wrap in plastic and refrigerate until firm, about 30 minutes.

　　

Step 3

On a lightly floured work surface, roll out the disk to 1/8 inch thick. Using a 2-inch round cookie cutter, cut out rounds and place about 1 inch apart on the prepared sheet. Bake, rotating the sheet halfway through, until the edges are golden, 18 to 20 minutes. Transfer sheet to a wire rack to cool 5 minutes. Transfer parchment paper and cookies to rack to cool completely.

　　

Step 4

Using an offset spatula, spread 1 tablespoon filling onto the flat sides of half the cookies. Sandwich with remaining cookies, keeping the flat sides down. Once filled, cookies can be kept in an airtight container in the refrigerator for up to 3 days.

　　

Grapefruit Cream Filling

Step 5

In the bowl of an electric mixer fitted with the paddle attachment, beat the butter and sugar until light and fluffy, about 4 minutes. Beat in the honey. Add juice, 1 tablespoon at a time, until filling holds together and is smooth and creamy, about 2 minutes. Transfer to a small bowl, cover, and set aside until ready to use.

　　Reprinted with permission from Martha Stewart's Baking Handbook by Martha Stewart. © 2005 Clarkson Potter