In a small saucepan, combine the dark syrup, sugar, butter, orange zest, cinnamon, cardamom, ginger, cloves, allspice, and black pepper over medium heat. Remove from heat once it comes to a boil and the butter has completely melted. Allow to cool slightly before transferring to a stand mixer or large bowl.
Once the mixture starts to simmer and the butter has completely melted, remove from heat. Allow to cool slightly before transferring to a stand mixer or large bowl
Beat the spice mixture until light and pale. Beat in the egg.
In a medium bowl, whisk together the flour, baking soda, and salt. Add to the beaten spice mixture until a soft and smooth dough comes together.
Divide the dough into two equal pieces, wrap in plastic, and refrigerate 8 hours to overnight.
Preheat oven to 350˚F (180˚C). Line two baking sheets with parchment or lightly grease.
Unwrap one pieces of dough and place on a floured surface. Keep the remaining dough in refrigerator.
Roll the dough into a thin sheet (between 1/8-1/4 inches, 3-5 millimeters thick), flouring as needed just enough to keep it from sticking.
Use cookie cutters to cut out desired shapes and arrange at least 1 inch (2.5 centimeters) apart on prepared cookie sheets.
Bake in preheated oven until slightly puffed and beginning to darken around the edges. Repeat with remaining dough.
Store in airtight container for up to a week. If desired, dust with powdered sugar or decorate with icing before serving.