This cake can also be made in a regular 9-inch (23cm) cake pan, one that is fine to heat on the stovetop if you don’t have a cast iron skillet. (If you don’t have a regular cake pan that can be put over direct heat, such as a glass or ceramic mold, you can heat the butter and brown sugar in a saucepan and pour it into whatever pan you’re using.) Don’t use a springform pan as the topping will almost certainly leak. If using frozen cranberries, no need to defrost them before using them. If you…