Beat the butter and sugar for the box until pale and smooth.
Add the eggs gradually and beat for one minute.
Mix in treacle, syrup, and vinegar at a low speed.
Incorporate the flour and dry ingredients to combine into a dough.
Divide dough into six portions, wrap in cling film, and chill for 20 minutes.
Preheat the oven to 190°C.
Roll dough into two 20cm squares and four 20x7cm rectangles.
Bake for 10-12 minutes and trim edges while hot to ensure straight lines.
Prepare royal icing by beating egg white and gradually adding icing sugar.
Assemble the box using icing and pipe decorative patterns on the surfaces.
Cream butter and sugar for the small biscuits and mix with flours, zest, and cinnamon.
Roll out the dough and cut shapes using a 6cm cutter.
Bake for 10-12 minutes and sprinkle with cinnamon sugar while warm.
Drizzle melted white and milk chocolate over the cooled biscuits.
Decorate the box lid with colored biscuit roses and leaves before filling with biscuits.