Have you ever sliced into a roast beef and the light caught the meat in just the right way so that it had a sheen like a rainbow or an oil slick on the road? That iridescent shimmer of pinks, yellows, ...

Rich, luxurious and labour-intensive to make, beef wellington is a real indulgence. Traditionally a large piece of fillet covered in a layer of duxelles – finely chopped mushrooms and shallots – and ...