Combine the brown sugar, paprika, coriander, onion, garlic, mustard powders, salt and pepper and spread it out on a baking sheet.
Using a paring knife to piece a dozen or so time both sides of the pork than place on the baking sheet and then flip the pork over so that both sides are coated in the spices.
Cover and place in the fridge for at least 4 hours or overnight