1Pre-heat the oven to 180°C/350°F/Gas Mark 4
2Season the cod fillets with salt and pepper
3Heat 1 tablespoon of the oil in a large non-stick skillet over a medium heat until very hot. Add the cod, flesh side down, and cook until lightly browned, about 2 minutes; turn over and cook for 1 minute longer. Transfer to a plate
4Return the skillet to the stove and heat the remaining 3 tablespoons of oil over a medium heat. Add the onion, garlic, anchovy, oregano, and crushed red pepper flakes; cook, stirring occasionally, until the onion softens, 4 to 5 minutes
5Add the tomatoes, olives, and capers, bring to a simmer, and cook until slightly thickened, about 5 to 6 minutes
6Stir in the parsley then add the fish, spooning some sauce over each fillet
7Transfer to the oven and bake for 8 to 10 minutes until the fish is cooked through and flakes easily with a fork
8Serve fillets with plenty of the sauce.