In a large bowl, beat the butter and brown sugar with a hand held mixer until light and fluffy. Gradually incorporate the flour and orange zest and spices, when the mix resembles breadcrumbs, knead by hand to bring dough together.
On a lightly floured surface, roll the dough into a log. Wrap and chill for at least an hour until firm.
Preheat the oven to 170C /150C fan forced. Cut the chilled dough into slices and bake for 10-15 minutes, or until the edges turn golden brown.
Remove from the oven and leave to cool on the tray for 10 minutes before decorating.