Cutting the shapes
Put the golden syrup, sugar, butter, lemon zest, ginger and mixed spice in a large saucepan. Stir gently over a low-medium heat until the sugar has dissolved. Turn up the heat and bring briefly to the boil. Remove from the heat and tip in the bicarb; the mixture will froth. Beat briefly to combine, then set aside to cool for 15 mins. In batches, fold the flour into the cooled mixture. Beat in the egg, scrape the dough onto a lightly floured surface and knead for 1 min. Wrap in clingfilm and chill for 1 hr.
Cut out a 14cm and an 18cm square template on thick paper or card. Roll out the gingerbread between sheets of nonstick baking paper to 4mm thick. Use cutters or a sharp knife and leave at least 2cm around each shape to keep the squares strong. Using the templates, cut out 6 small and large squares of gingerbread and transfer to lined baking trays. Put in the freezer for 5 mins to firm up. Remove 3 of the smaller squares from the freezer, cut out decorations, then return to the freezer for 5 mins. Meanwhile, use the remaining dough to cut out gingerbread people or other shapes around 8cm long. Transfer these to a lined baking tray and freeze for 5 mins.
Preheat the oven to gas 5, 190°C, fan 170°C. Bake in batches – the dough squares for 12-14 mins and the gingerbread people for 6-8 mins – until golden brown at the edges. Leave to cool and set for 5-10 mins on the trays, then transfer to wire racks to cool completely.
Cook's tip: Keeping the dough on the nonstick baking paper you rolled it out on stops it losing its shape when you move it around.