You can make parkin several days in advance and store at room temperature in a sealed container, it is said to improve with a few days resting.
Made this last night and by this morning it was perfect. Moist, soft and sticky and lovely with my morning coffee -- I will make again for Bonfire night after doing this successful trial run! Thanks for posting! - 26 Oct 2014
I think this is a very good base recipe, with a few tweaks - use plain flour & 1/2 tsp bicarbonate of soda, OR self-raising flour with no extra agent. I had plain flour and used the 1 tsp as stated, and my parkin did indeed sink in the middle. However, it's still delicious! Also, I used soy milk and dairy-free butter as I was making this for someone with a dairy allergy. The only additions I made were to add 1 tsp of ginger and 1/2 tsp nutmeg. This makes, in my Yorkshire in-laws' opinions, a more authentic parkin. I'll make this recipe again. - 09 Nov 2017
I wanted this to work so badly, and the batter tasted gorgeous! It wasn't a total disaster, I'll just make some tweaks next time (leave out the bicarb). When the Parkin went in the oven, it rose up incredibly quickly around the sides, then the middle just sank. I hadn't opened the oven door at all, I was just watching it through the door. It was ready in half an hour too; probably because it had climbed up the sides of the tin and the centre was very thin. All I can think is that my bicarb/ SR. four mix was too potent. I've looked at other recipes, and noticed that most don't normally double up on the raising agents. I'll still come back to this recipe, as taste-wise it's the nicest Parkin ever. Mine just doesn't look good enough to share. Which may not be a bad thing- all for me!! - 07 Nov 2014