Lebkuchen (German Honey Bars)

Honey bars:
1 cup (320g) honey
2 tablespoons (30g) water
6 tablespoons (3/4 stick or 85g) unsalted butter, cut into cubes
¾ cup packed (175g) brown sugar
2 large eggs, lightly beaten
Finely grated zest of 1 lemon
1 tablespoon (15g) lemon juice
2 ½ cups sifted (300g) all-purpose flour
½ teaspoon baking soda
1 tablespoon ground cinnamon
1 teaspoon ground cloves
½ teaspoon grated or ground nutmeg
¼ teaspoon ground cardamom
¼ teaspoon ground anise
½ teaspoon salt
1/3 cup chopped blanched almonds
1/3 cup chopped citron
1/3 cup chopped candied orange peel
Citrus glaze:
1 ¼ cups powdered sugar, sifted
Finely grated zest of 1 lemon
2 tablespoons lemon juice
½ teaspoon vanilla
Decoration:
Candied cherries (optional)
Blanched almonds (optional)

Honey bars:
Heat honey and water in a large heavy saucepan until runny. Remove from heat, and stir in butter until melted. Transfer mixture to a large bowl and stir in brown sugar, eggs, lemon zest, and lemon juice.
In a medium bowl, whisk together flour, baking soda, spices, and salt.
Add the flour mixture to the honey mixture and stir just until combined. Add almonds, citron, and candied orange peel. Stir until the dough is smooth. Cover the dough tightly with plastic wrap and refrigerate at least 24 hours or up to 1 month.
When ready to bake, preheat the oven to 375°F. Grease a 13x9x2-inch baking pan and line with parchment paper so it extends over the 2 long sides.
Firmly press the dough into the prepared pan to form a smooth, even layer. Bake until a toothpick inserted in the center comes out almost clean, about 30 minutes.
Citrus glaze and decoration:
In a medium bowl, beat together powdered sugar, lemon zest, lemon juice, and vanilla until smooth. While the lebkuchen is still warm, spread glaze evenly over the top.
Mark into bars by cutting into the lebkuchen about ¼ inch deep with a knife. Decorate, if desired, by placing 1 candied cherry in the center of each bar. And arrange 4 blanched almonds around each cherry.
Let stand in the pan on a rack until completely cool and the icing is set. Using the overhanging parchment as handles, transfer to a cutting board. Cut into bars. If possible, let the cookies age for at least 2 weeks to allow the spices to ripen. Lebkuchen will keep for months in an airtight container.