Preheat the oven to 350°F (175°C). Line a baking pan with parchment paper for easy removal.
Prepare the dry ingredients: In a medium bowl, mix the flour, ground almonds (or hazelnuts), baking powder, salt, cinnamon, nutmeg, cloves, and ginger. Set aside.
Cream the butter and sugar: In a large mixing bowl, cream together the softened butter and brown sugar until light and fluffy. This may take about 2-3 minutes using an electric mixer.
Add the honey and egg: Beat in the honey and egg until well combined.
Combine the wet and dry ingredients: Gradually add the dry ingredient mixture to the wet ingredients, stirring until a thick batter forms.
Spread the batter: Transfer the batter to the prepared baking pan and spread it evenly with a spatula. Smooth the top to ensure even baking.
Bake: Bake for 25-30 minutes or until the top is golden and firm to the touch. Allow the bars to cool completely in the pan.
Make the glaze: In a small bowl, whisk together the powdered sugar, lemon juice, and a little water until smooth. If the glaze is too thick, add more water, one drop at a time.
Glaze the bars: Once the bars are completely cool, pour the glaze over the top, smoothing it out with a spatula. Allow the glaze to set for a few minutes.
Let them sit: Cover the bars and let them sit for a week or so to deepen the flavor, just like the traditional recipe from Nuremberg. The bars will become soft and flavorful as they rest.

Enjoy your homemade Nuremberg Christmas Bars!