Put the dried mushrooms in a heatproof bowl and pour over 300ml boiling water from the kettle. Leave to soak.

Meanwhile, heat the oil in a large frying pan over a low-medium heat, and cook the onion for 10 mins until starting to turn golden. Tip in the chestnut mushrooms, add some seasoning, and cook for another 8-10 mins until softened.

Stir in the miso paste and flour, turn up the heat and cook for a further 1-2 mins. Tip in the rehydrated mushrooms and most of their soaking liquid – leave the last few drops in the bowl, as it may contain grit. Stir well, add the stock and bring to a simmer.

Gently simmer for 10-15 mins, until thick enough to coat the back of a spoon. Check for seasoning. If you prefer a thicker gravy, blitz with a hand blender until smooth. If you prefer a thinner gravy, strain and discard the onions and mushrooms before serving. Will keep frozen for up to three months.