For the icing
1 egg white squeeze of lemon juice about 300g icing sugar, sifted
Cream the butter and sugar in a mixer. Add the spices, zest and treacle or molasses, and beat again, then add 2 tbsp of the milk. With the beater on a low speed, add the flour and bicarbonate of soda.
Scrape the dough off your beaters and, using your hands, bring the dough together into a ball. Add more milk if you need to, but don’t let the dough become sticky. Wrap in cling film and put in the fridge for an hour.
Lightly flour a work surface and roll out the dough 3mm thick. Stamp your shapes and put them on to two lightly buttered baking sheets. Gather the remaining dough into a ball, roll out again and keep stamping until it has all been used.
Put the sheets in the fridge for about 45 minutes and heat the oven to 180C/170C fan*/gas mark 4. Cook the biscuits for 12 minutes.
They should start to feel firm round the edges as they cool and eventually become really hard – they need to have a nice ‘snap’.
To make the icing, gently beat the egg white, then add the lemon juice and as much icing sugar as needed – it should be really thick if you are going to pipe it, thinner if you plan to drizzle it. Decorate as you like.