In a food processor, combine all the dough ingredients: flour, spices, baking soda, egg, brown sugar, honey, and molasses. Blend until the mixture forms a smooth dough that pulls away from the sides of the bowl, which should take about 2-3 minutes. Wrap the dough in plastic wrap and refrigerate it overnight.

Preheat your oven to 375°F (190°C). Divide the chilled dough into two halves and roll one half into a long rope, about 1 inch in diameter. Cut the rope into 1-inch pieces, then shape each piece into small rounds. Place on parchment-lined baking sheets in a little space between them to allow puffing during baking.

Bake the shaped cookies for 12-15 minutes, until puffy and slightly cracked on top. Keep a close eye to prevent overbaking. Once baked, let cool on the baking sheet for a few minutes before transferring to a wire rack.

Prepare the glaze by whisking together the icing sugar, egg white, and lemon juice in a bowl until smooth and glossy. The glaze should be thick enough to coat a spoon but pourable.

Once the cookies have cooled for about 10 minutes, use a pastry brush to generously coat the tops with the lemon glaze. Allow the glaze to set for about 20 minutes at room temperature.

Melt dark chocolate in a heatproof bowl over simmering water, stirring until smooth. Dip the bottoms of each glazed cookie into the chocolate, shake off excess chocolate and place them on a parchment-lined baking sheet to set for 30 minutes to 1 hour.

After the chocolate has completely set, store your Lebkuchen cookies in airtight containers to maintain their softness. They can be kept at room temperature for weeks.