Published May 1, 2007. From Cook's Illustrated.
We found one store-bought brand that would do—in a pinch.
After sampling six store-bought Cajun spice rubs, we found that mixing your own delivers superior results. But if you really want to buy a rub, Paul Prudhomme's Blackened Redfish Magic has the best blend of flavors.
Our advice to improve any spice rub that's going to meet a hot grill? To give fish a flavorful "blackened but not burned" coating, bloom the spice mixture in melted butter, allow it to cool, and then apply the coating to the fish. Rub the toasted spice mixture into both sides of the fish for maximum flavor. Once on the grill, the spice crust will acquire the proper depth and richness while the fish cooks through.