Method

• 1.
  For the fermented chilli, place all the ingredients in a food processor and whiz, scraping down the sides occasionally, until a rough paste. Transfer chilli mixture to a sterilised jar with a lid and stand at room temperature (about 22°C-23°C) for 1 week. Fermented chilli can be stored in the fridge for up to one year.
• 2.
  Bring a large saucepan three-quarters full of salted water to the boil over high heat. Cook spaghetti according to packet instructions.
• 3.
  Meanwhile, heat a large non-stick, heavy-based, deep frypan with oil over high heat. Season mackerel all over then sear, skin-side down, for 1-2 minutes or until the meat just starts to cook.
• 4.
  Add 3 large tbs of chilli paste then stir frequently but gently to break up the fish slightly and prevent paste from sticking.
• 5.
  Add wine, scraping the bottom of the pan with a wooden spoon, then add stock. When pasta is ready, add straight from the saucepan (you will need pasta water to keep the dish from drying out).
• 6.
  Reduce heat to medium and simmer gently for 2-3 minutes, then stir in the parsley. Season to taste. Add butter, reduce heat to low and toss the pan until butter melts and the sauce is a coating consistency. Use extra pasta water to adjust the sauce if needed. Season to taste and serve with lemon wedges.