In a 6-inch sauté pan, add cooking oil over high heat. Season black cod with salt and pepper on both sides, then sear presentation side down. Add remaining 2 tablespoons of butter, letting it brown.
The Festive Set Menu at the Ivy Blackheath will run up until January 2, with two courses priced at £50 and three courses priced at £55, with some courses costing an additional supplement charge.