Start the day before you want to bake the cookies.
Place the butter, sugar and syrup in a pan and heat gently until melted. Do not allow the mixture to boil.
Remove from the heat and stir in the cinnamon, ginger, cloves, allspice and bicarbonate of soda.
Add the flour and stir until no dry lumps remain. Finally mix in the almonds.
Allow the dough to cool for a few minutes, just until you can handle it, then scrape it out onto a large piece of baking parchment. Use your hands to shape it into a log. The dough may feel greasy, that is fine.
Wrap the log of dough tightly in the parchment and twist the ends tightly to seal it.
Leave the dough to rest overnight at room temperature. It will firm up as it sits.
The following day, preheat the oven to 180°C/160°C fan/350°F/gas mark 4. Line a couple of baking sheets with baking parchment.
Use a very sharp serrated knife to gently slice the log into thin slices, no more than 4mm thick, thinner if you can.
Place them spaced apart (they will spread as they cook) on the lined baking sheets and bake for 8-12 minutes until lightly browned around the edges and on the underside.
Allow to cool on the trays for a couple of minutes then gently transfer them to a wire rack to cool completely. They will become crisp as they cool. Once cold, store in an airtight container.