Cut 1 stick cold unsalted butter into small pieces. Finely grate the zest of 1 to 2 medium lemons until you have 1 tablespoon. Set aside the lemon to juice for the icing. Lightly beat 2 large eggs in a small bowl.

Place the lemon zest, 2 ¼ cups all-purpose flour, ⅓ cup granulated sugar, 1 teaspoon baking powder, and ½ teaspoon kosher salt in the bowl of a food processor fitted with a blade attachment. Pulse a few times to combine. Add the butter and process until the butter is evenly distributed, 10 to 20 seconds. With the motor running, add the eggs and 2 teaspoons vanilla extract through the feeding tube. Process until a dough ball forms on the blade, about 1 minute.

Remove the dough from the food processor and divide in half. Roll each portion into a fat log and flatten slightly. Wrap each log tightly in plastic wrap and refrigerate for at least 1 hour and up to 2 days. Meanwhile, make the filling.

Trim the stems from 20 dried figs and halve each fig (about 1 cup). Pit and halve 6 dried dates (about ½ cup). Transfer the figs and dates to food processor fitted with a blade attachment. (No need to wash out the bowl.)

Add ½ cup walnut halves, ¼ cup slivered almonds, ¼ cup golden raisins, ¼ cup marmalade, 2 tablespoons brandy, whiskey, or dark rum, 1 tablespoon honey, 1 teaspoon ground cinnamon, ½ teaspoon kosher salt, and ¼ teaspoon ground allspice. Pulse until no large pieces of nuts or raisins remain, scraping down the sides of the bowl with a spatula as needed. Some texture is great, it does not need to be a smooth paste. Transfer to a bowl and refrigerate until ready to assemble the cookies.

Arrange 2 racks to divide the oven into thirds and heat the oven to 350ºF. Line 2 baking sheets with parchment paper.

Unwrap one piece of dough and place on a well-floured work surface. Roll into a rectangle slightly larger than 8x10-inches. (If the dough starts to crack, just push it back together — it’s quite forgiving.) Trim the long edges, then double check it measures 8 inches wide. Halve the dough lengthwise to make 2 (4x10-inch) rectangles. Make sure they aren’t sticking to the work surface. Set aside 1 rectangle while you fill the first.

Take ¼ of the filling mixture and roll it into a 10-inch log with wet hands to prevent sticking. With a long side of the dough closer to you, place the filling down the middle of the rectangle. Carefully lift and wrap the top third of the dough over the the filling, then roll the dough and filling over the bottom third, continuing to roll until the seam is facing up. There should be a small overlap. Carefully pinch the seam shut.

Roll it over again so the seam is on the bottom, and gently roll along the length to seal. Trim the ends. Cut the log in half crosswise, then cut each half into 4 pieces, each about 1 ¼-inches long. Place on the prepared baking sheet. (They won’t rise or spread much, so can be placed fairly close together.) Repeat with remaining dough and filling.

Bake for 12 minutes. Rotate the baking sheets from front to back and between racks. Bake until firm and the bottoms are lightly golden, 8 to 10 minutes more. Transfer the cookies to wire racks and let cool completely.

Arrange the cookies on the wire rack over a baking sheet. Place 2 cups powdered sugar, 2 tablespoons lemon juice, and 2 tablespoons milk in a small bowl and whisk until smooth. Dip the tops of the cookies in the glaze and return to the rack glazed-side up. Let sit for about 30 seconds, then sprinkle with nonpareils if desired. Let the glaze set completely before serving.