1) Preheat the oven as high as it goes, 260C/Gas 10.
2) Liberally coat the fillets with the olive oil and steak seasoning. Place the meat on a roasting rack or in a roasting pan and put it in the oven. If you are cooking in a pan with no rack, add a splash of water to the pan. Roast the meat for 10 minutes on high then reduce the heat to 180C/Gas 5 and cook for 30 minutes more. Do not open the oven during those first 10 minutes. Remove the meat from the oven and let it rest for 10 minutes before serving.
3) Place the roasted red peppers in a food processor and add the garlic, parsley, olives, salt and pepper. Turn the processor on and pour in the olive oil, about 3 tablespoons.
Thinly slice the meat against the grain and serve with the sauce and crusty bread.