Colcannon
I love potato dishes and this appears as a side dish to a roast ham, and is another great use of too much mash leftover, great made with either Kale or Cabbage (Savoy) type. The Irish serve it with a great lump of butter in the middle but I form it into sort of crunchy patties. And the crunch is what this is about.
In a little butter fry your mash until it starts to brown, then break it up and continue, then break it up and continue, then break it up and continue, it takes sometime. Then add your chopped cabbage and continue.