Preheat the oven to 220C/200C Fan/Gas 7. Heat the butter and oil together in a shallow, flameproof casserole over a low heat. Add the onion and cook for 5 minutes, stirring regularly until softened.

"This dish is the essence of my fast food. Season a fillet of salmon and nutty bread crumbs right on your serving platter and bake it in a very low oven while you make another dish or entertain your ...