The answer at https://chinese.stackexchange.com/posts/9675/revisions offers "这道菜" to say "this kind of food". This looks like a very useful phrase, which I had not seen before (and if I've heard it, it did not stick with me, but that could easily happen). How widely can you use 这道 for "this kind"? What kinds of things would it apply to? Is it informal, slangy, quite formal?