To make the rub, combine the brown sugar, Cajun spice and salt. Wash the salmon with the rum and leave to marinate for 30 minutes.
Massage in the secret rub and leave to marinate in the refrigerator for 2 hours.
Remove the salmon from the refrigerator and allow it to come to room temperature.
Remove excess spice mix with your hands.
Combine ketchup and soy sauce in a small bowl and rub over the salomn to glaze it.
Prepare a kettle barbecue for indirect cooking, building a small coal fire on both sides of the grill and allowing it to burn quite low until almost out. Add 2 handfuls of pre-soaked woodchips to both sides
And allow them to start smoking well, with the lid on. If you have a thermometer, the temperature should be around 80–100.C.
Place the salmon on the grill, away from the heat source. Replace the lid and smoke for 40 minutes. Do not lift the lid, because if you’re looking, you’re not cooking!
Check the fish after 40 minutes, when it should be just cooked.
Remove from the barbecue and allow it to rest before serving.
Serve with horseradish potatoes and a fresh herb salad.
Cajun Spice Mix
Heat the oil in a wok. It needs to be hot! It should be about 150C, or able to cook a slice of bread to a golden color in 20 seconds.
Cook the onion and garlic separately, moving them around constantly so they cook evenly. Remove them from the heat when they start to turn a light golden color, and place them on paper towels to cool and drain. You’ll notice they will continue to color.
Place the drained and cool fried onion and garlic in a hand-held food processor, along with the remaining ingredients, and blitz to a rough powder.
The spice will keep for 1 month if stored in an airtight container.