My husband actually turned me on to this recipe, but as the version he sent me called for a specific type of Chinese mustard, I am actually sharing a slightly different recipe, which says it can be made with just about any type of mustard greens, or radish or turnip greens.
I haven't tried this yet, but plan to do so soon - it sounds so delicious and I've been craving fermented foods since my summer cabbage didn't turn out that well, so I haven't made any kimchi or sauerkraut in a while!
Whether you're a fan of pickled mustard greens, or just looking to try a new ferment, you may find this recipe of interest.