Heat the oven to 160C (140C fan)/310F/gas 2½. Weigh out the treacle, syrup and butter into a medium saucepan (I recommend using a spoon dipped in boiling water to make life easier with the sticky ingredients – they should just slide off) and place on a medium heat, stirring occasionally, until melted together. Do not let the mix come to a boil.

Take off the heat and set aside. Generously grease a roughly 20cm baking tin (or an 18cm x 23cm rectangular one, though a little bigger or smaller won’t matter too much) with the extra butter and line with baking paper, if necessary making small cuts in the corners to help it fit better.

Combine the flour, oatmeal (if you prefer a rougher texture, use coarse oatmeal instead), spices, sugar, salt and bicarb in a large bowl and whisk to mix. Pour the treacle mixture into the dry ingredients, stirring until no more dry pockets of flour are visible.

Beat the egg with the milk, then stir into the cake mixture to create a batter that’s loose enough to pour into the tin – if it’s still a bit too thick, add a little more milk.

Pour into the tin, level the top, then bake until it’s just firm in the centre and the cake springs back when pressed with a cautious finger – this will probably take between an hour and a half and an hour and three-quarters, but check it regularly towards the end to ensure the parkin doesn’t overcook.

Leave the cake to cool in the tin for at least 30 minutes, then turn out, cut into squares and either serve warm (it’s lovely with ice-cream) or leave to cool completely and store in an airtight tin for up to three weeks. Like malt loaf, the texture will improve after baking and become stickier with time.