How to Make It
In a small saucepan, combine the honey with the granulated sugar and salt. Cook over moderate heat, stirring occasionally, until the honey and sugar are melted and beginning to simmer, about 3 minutes. Transfer to a large heatproof bowl and let cool slightly, about 20 minutes.
Preheat the oven to 350° and line a large rimmed baking sheet with parchment paper. In a small bowl, sift the flour with the baking powder. Using a sturdy spatula or wooden spoon, stir the egg into the honey mixture. Stir in the almonds, candied orange and citron peels, orange and lemon zests, cinnamon, cloves and nutmeg, then stir in the sifted flour.
Scrape the dough onto the prepared baking sheet and, with floured hands, press into a 12-by-9-inch rectangle, about ¼ inch thick. Bake for about 20 minutes, rotating the baking sheet halfway through, until golden and puffy.
Meanwhile, in a small saucepan, combine the confectioners’ sugar with 2 tablespoons of water and bring to a boil over moderately high heat. Boil the syrup until it begins to thicken, about 5 minutes. Keep warm.
As soon as the leckerli is done, brush the surface with the hot glaze. While it’s still hot, carefully slide the parchment onto a work surface. Using a sharp knife, trim the edges of the rectangle and cut the leckerli into 2-by-1-inch bars. Let cool before serving.