Prep butter with the fish Enough background, let's start right away. Simply make the black rub by mixing all the spices together well and heat up your BBQ to 250 °C. Get a cast iron pan or plancha. The latter is a cast-iron baking plate, but plancha sounds much more international, so that is what we are going for. Where were we? Oh yes ... place the plancha on the grill and let it get really hot. First of all, spoil the sea bass fillets by greasing them with melted butter. Then dip the buttered perches in the black rub. Burn it black but do it right. Grease your cast iron plate well with sunflower oil. Grill the sea bass on both sides for about 2 minutes, it goes nice and fast because of the infernal temperature. A core temperature of 60 °C is okay. The crust of the herbs hardens by itself and then comes off easily. So be patient, don't touch it, wait a while and above all, don't touch anything.