Preheat oven to 350Fº. Line 2 rimmed baking sheets with parchment paper.

Make the dough: add the flour, sugar and lemon zest to the bowl of a food processor and pulse until combined. Add butter and pulse until it resembles a coarse meal. Add egg and vanilla. Pulse just until mixture forms a ball of dough. Wrap dough in waxed paper and chill while you prepare the filling (reserve food processor bowl).

Make the filling: Add the figs, raisins and chocolate to the bowl of the food processor. Pulse until fruit and chocolate are coarsely chopped. Add remaining filling ingredients and pulse it forms a mostly smooth paste (it’s okay if it’s slightly chunky).

Divide dough in half. Roll each piece into a 9-inch by 7-inch rectangle, then cut each piece in half lengthwise for a total of 4 rectangles.

Divide the filling onto each piece of dough then spread down the center lengthwise. Fold outer edges of dough over filling and pinch ends closed. Turn dough over, with seam facing down, and cut each log into 8 equal pieces. Place cookies onto prepared baking sheets.

Bake cookies, one sheet at a time, until bottoms are lightly golden, 15–20 minutes. Let cookies cool on baking sheets until firm enough to transfer to a wire rack. Let cool completely before icing.

If icing cooking, in a small bowl, whisk confectioners’ sugar with a splash of vanilla and just enough water until thick and smooth (you want it to drape the cookies in a thick glaze). Spread icing over tops of cookies, then sprinkle with nonpareils, if desired.