Open the cider so that it loses its fizz. Preheat the oven to 170C/150C Fan/Gas 3. Grease your bundt tin with non-stick cooking spray, or simply oil it, and leave the tin upside down on a piece of newspaper or baking parchment while you get on with the batter.
Measure the oil, brown sugar and (whether youâ€™re weighing it or going for volume and using a cup measure, always lightly oil the receptacle for the treacle first and it will slide out easily) black treacle into a bowl.
Pour in the cider and crack in the eggs, add the ginger and beat till smooth. While I use a freestanding mixer to make this cake, itâ€™s simple enough by hand: in which case, beat the eggs together first before adding to the other ingredients.
In another bowl measure out the flour, baking powder, bicarb, nutmeg, five-spice and cinnamon, and fork through to combine.
Gently tip the dry ingredients into the wet treacly mixture, beating as you go to make a smooth batter. Scrape the sides and the bottom of the bowl well to make sure there arenâ€™t any pockets of flour.
Pour the dark and aromatic batter into the prepared tin: it will be very runny, but donâ€™t be alarmed. Place in the oven to bake for 45â€“50 minutes, but start checking after 40. When the cakeâ€™s ready, it will start to come away from the sides of the tin and a cake tester should come out clean; thatâ€™s to say, not wet, but with some crumbs adhering to it. Transfer the bundt to a wire rack for about 30 minutes, then use your fingers to help prise the cake away from the edges of the tin, most particularly around the funnel, and turn out. Leave to cool completely before wrapping, first in parchment and then foil, as it tastes best if eaten the next day. I donâ€™t always manage this.
For the sauce, melt the butter, sugars and syrup in a small, heavy-based pan and let it simmer for 3 minutes, swirling the pan every now and then.
Add the cream and the smoked salt and swirl again, then give it a stir with a wooden spoon, and taste. Go cautiously so that you donâ€™t burn your tongue, and see if you want to add more salt, before letting it cook for another minute. Let it cool a little then drizzle over the cake and pour any remaining sauce into a jug to serve.