Parkin waits in a tin for a few days before I slice it

In November my kitchen smells of black treacle and ginger at least once a week, because that is when I bake parkin. It is a dark, sticky oat and ginger cake from the old northern baking tradition, and it belongs to bonfire weather, cold hands and early dark evenings. Parkin has one odd habit that I have learned to trust: it is not at its best on the day it is baked. Fresh from the oven it is firm and a little dry. Wrapped and left in a tin for a few days, it turns soft, dark and sticky. So I bake it on a Sunday and we do not slice it until the middle of the week.

I use a 20 cm square tin, greased and lined with baking paper, and heat the oven to 150°C (130°C fan, gas 2). Parkin bakes low and slow, because treacle and syrup scorch easily. In a saucepan on a low hob I melt 115 g of butter with 75 g of dark brown soft sugar, 4 tablespoons of golden syrup and 2 tablespoons of black treacle. The treacle is thick and stubborn, so I warm the spoon in hot water first. I stir until it is smooth and melted, and I do not let it boil.

In a big bowl I mix 115 g of self-raising flour, 115 g of medium oatmeal or porridge oats whizzed for a few seconds, 2 teaspoons of ground ginger, a pinch of nutmeg and a pinch of salt. I pour the warm dark syrup into the dry mix, then add 1 beaten egg and 2 tablespoons of milk, and stir until it is a loose, glossy batter. It looks almost like melted chocolate. I do not taste it: the Food Standards Agency advises against eating raw batter, because uncooked flour is not usually treated to kill bacteria, and there is raw egg in it too. Bowl, spoon and hands get a wash with warm soapy water.

It bakes for about an hour, until firm to the touch and a skewer in the middle comes out clean. Do not worry if the middle dips a little as it cools; parkin often does, and that sunken centre is the stickiest part. I leave it in the tin until it is cold, then lift it out, wrap it in baking paper, then foil, and put it in an airtight tin.

Then I wait. For the first day nothing much happens. By the second day the crust has softened. By the third it has gone dark and tacky, the ginger tastes warmer and the oats have soaked up the syrup. I usually cut it on the third or fourth day into thick squares, and it keeps happily in the tin for another week or so, if anyone lets it.

Why does the waiting work? The oats and sugar slowly draw moisture from the air and from each other, so the cake gets stickier rather than staler. I cannot give you a chemistry lesson, only what I see in my kitchen: a Sunday parkin is a different cake by Wednesday.

We eat it in thick squares with a cup of tea, or warmed for a few seconds with a spoon of custard after supper, and it is very good wrapped in paper in a coat pocket on a cold walk. Contains egg, milk, wheat (gluten) and oats, which can also contain gluten.

So if you bake parkin this week, give it time. Wrap it, put the lid on the tin and leave it alone. Do you have a cake that is better after a few days than on the first?