This is a Jamie Oliver's idea so I can't take credit for it, as much as I'd like to. Don't be put off by the anchovies in the butter, it doesn't taste fishy and you can't detect them at all. In fact, you can't really detect the rosemary or garlic much either for that matter. They act more like a seasoning as opposed to a flavouring and I promise you this is seriously the best cabbage you'll ever eat! Cook the cabbage as described and adapt the recipe to make as much or as little of the butter as you like, the rest can be stored in the freezer for those 'gotta have my cabbage' moments. Ha ha, you say that now. . . .