The recipe appears in my cookbook, A Celebration of Food (published in 2012), and last year, I made a video, demonstrating the technique. Since then I've adjusted the method: rather than steaming the dried scallops to soften them (a necessity, because they won't get softer once you start cooking them with the oil), I now simmer them in water, which makes it easier to shred them into small pieces. I was reluctant to try this at first, worrying that the flavour of the scallops would get diluted, but it doesn't. So ignore the steaming step in the video and cookbook, and follow this technique, instead. Another new technique - use the chopper attachment of a food processor or immersion blender to shred the scallops, but don't overprocess them.
Use the smallest dried shrimp you can find.
500 grams dried scallops
300 grams shallots, minced
12 large garlic cloves, minced
100 grams small dried shrimp
75 grams Chinese dried ham
6-8 red bird's-eye chillies
About 10 grams fine chilli flakes
60ml fish sauce or soy sauce
1 heaped tbsp dried shrimp eggs
1 litre canola or corn oil, plus more as needed
Rinse the dried scallops. Pour 500ml of water in a wide saucepan and bring to the boil. Add the scallops and cover with the lid. Simmer, stirring often, until the scallops are very soft and have absorbed all of the water (about 15 minutes). If they seem dry, stir in more water. While the scallops are still hot, pull them apart into fine shreds, discarding any hard bits.
Cut the ham into 3mm cubes. Remove the stems and seeds from the bird's-eye chillies, then mince the flesh.
Pour 500ml of oil into a wok then add the shallot. Heat over a medium flame, stirring often, until the oil starts to sizzle. Stir in the scallop, garlic, shrimp, ham, chilli, 10 grams of chilli flakes and the fish sauce or soy sauce. Mix well then add another 500ml of oil. Bring to a simmer then lower the heat and cook very slowly - the oil should sizzle very gently. Cook for at least three hours, stirring often, and add more oil as needed when the mixture becomes dry. After three hours, stir in the shrimp eggs (and more chilli flakes, if desired) and cook for two more hours, or until the mixture is dark, thick and oily.
Ladle the XO sauce into a large, sterilised jar and pour in more oil so the ingredients are submerged. Store in the fridge, and decant into smaller jars as needed.