In a medium saucepan, combine water, sugar, and honey, heating over medium heat until the sugar dissolves, about 5 minutes.

Finely chop the mixed candied citrus peel.

In a large mixing bowl, combine the flour, chopped candied peel, ground hazelnuts, cocoa powder, lemon zest, Lebkuchen spices, cinnamon, baking soda, baking powder, and fine sea salt. Whisk together until fully blended.

Once your honey mixture has cooled, add it to the dry ingredients along with the egg and milk. Mix until a stiff dough forms.

Wrap the dough tightly in plastic wrap and chill in the refrigerator for at least 4 hours, or overnight if possible.

When you’re ready to bake, remove the dough from the refrigerator and let it sit at room temperature for about 30 minutes. Preheat your oven to 350°F (180°C).

Divide the chilled dough into 8 equal portions, rolling each into a rope about 11 inches long. Place the ropes on baking sheets lined with parchment paper.

Bake the cookies in your preheated oven for 12-14 minutes, until the edges are set but the centers remain soft.

While the cookies bake, prepare the glaze by mixing icing sugar, unsweetened cocoa powder, lemon juice, and enough water until it reaches a thick yet pourable consistency.

Brush the warm cookies with the prepared glaze as soon as they come out of the oven and allow them to cool on a wire rack before slicing them into diamond shapes.