Dec 8, 2022
Rumbledethumps: The Scottish Way to Eat Leftover Mashed Potatoes for Breakfast
Let me preface this by saying that there's no such thing as "too many mashed potatoes," but I am definitely guilty of always making too many mashed potatoes. Dinner for me and my roommate? A five-pound bag should be enough. This means I am regularly tasked with figuring out what to do with the remaining four-ish pounds of mashed potatoes the next day (and the next day… and sometimes the day after that). Shepherd's pie is always an option, and in regular rotation in our house. Sometimes I'll just fire up the griddle and fry a patty of leftover mashed potatoes until crispy and deep golden brown on both sides to have with breakfast.
I thought I'd run out of things to do with leftover mashed potatoes until I stumbled across a recipe for the delightfully named rumbledethumps in Ben Mervis's The British Cookbook. At first glance, the dish seems to be a cousin of colcannon, an Irish staple of mashed potatoes and cabbage, though this version is covered in cheddar cheese and baked in a casserole dish. In fact, Mervis calls rumbledethumps "Scotland's answer to the English bubble and squeak." The latter is leftover mashed potatoes and cabbage mixed together, sometimes with bacon or onions, and pan-fried until crispy.
As Mervis describes it, all three of these are related recipes that make the most of what's around, which, in this case, is potatoes and cabbage (and sometimes kale, according to Mervis). He tells me that bubble and squeak is typically served at breakfast, while colcannon is more of a lunch and dinner dish, and rumbledethumps can be made any time of day. And where do they get their names? Mervis tells me that rumbledethumps "is said to come from the process of mashing the potatoes (rumble) and popping them into the dish (thump). Fantastic, isn't it?" Meanwhile, "bubble and squeak gets its name from the sound it makes when it hits the pan of hot oil." Colcannon, which Mervis believes is likely the earliest invention of the three, is the only one without an onomatopoeic name. "The 'col' in colcannon likely comes from the Irish cál," which means cabbage or kale.
Of the three, Mervis describes rumbledethumps as the most "glammed up," served in a baking dish and covered in gooey shredded cheese. It's beautifully simple to make, consisting of just a few ingredients, and it tastes rich and homey. Mervis calls it a sort of breakfast casserole, and I have to say that the dish goes very well with some thick, crispy bacon and a couple of fried eggs, all the essentials for a hangover cure.
If you're making rumbledethumps without the help of leftover mashed potatoes, start by boiling potatoes until fork-tender, boiling sliced cabbage until soft. Then you just mash these two components together with lots of butter, scoop it all into a baking dish, cover with cheese, and bake. The end result is fluffy mashed potatoes, properly enriched with buttery flavor, bits of tender cabbage throughout, and gooey, salty, nutty cheddar bringing it all together.
If you find yourself swimming in mashed potatoes after your next big holiday meal, rumbledethumps are your brunch move. If you've already got leftover mashed potatoes and cabbage, most of the work is already done, giving you time to sleep in before firing the oven back up for your hungry guests.