Aldi recently launched the new colour range of its budget cast-iron casserole dishes, an annual occurrence since at least 2015. While other retailers including Marks & Spencer, Sainsbury’s, Argos and John Lewis also stock cheap cast-iron, Aldi’s, at £19.99, is by far the cheapest. It’s also only available “while stocks last”. The Guardian’s journalism is independent. We will earn a commission if you buy something through an affiliate link. Learn more. Any cookbook worth its salt will, at some point, tell you to simmer/boil/fry/saute something in a “heavy-bottomed” pot or saucepan. Contrary to lightweight postwar aluminium fare, a pot with…