Parkin is a sticky cake flavoured with syrupy molasses, oatmeal and ginger, traditionally enjoyed on Bonfire Night in the north of England. Like a fine wine, parkin improves with age, so bake it up to a week before you want to eat it.
Heat the oven to 160°C/140°C fan/315°F/Gas 2–3.
Beat the egg and milk together in a jug.
Place the butter in a large pan with the molasses or treacle, golden syrup and sugar. Melt everything together over a low heat, stirring occasionally.
Remove the pan from the heat and stir in the oatmeal, flour, ginger and mixed spice. Add the egg and milk mixture and stir until well combined.
Pour the mixture into the prepared tin and bake for 50 minutes to 1 hour, until the sponge is firm to the touch, but not dry. Leave the sponge in the tin until completely cold, then wrap it (still in the tin) in baking paper and foil. Store for a week, then turn out and cut into 16 squares. Eat within 2 weeks.