Bubble and squeak is the British dish nobody outside Britain orders on purpose, which is exactly why bringing it to Bobby's kitchen was the move. It is leftover potatoes and cabbage, fried hard in butter or beef fat until the outside is crisp and the inside is unified. It is, in a word, a hash. And hashes are won or lost on the crust.
Robert Aikens runs Las Gemelas Cocina Mexicana in DC — a Mexican spot, yes, despite the British dish credentials, because chefs are not their childhood cuisine and never should be. His bubble and squeak had a crust that the judges audibly noticed. Bobby's, per the broadcast, was "soft throughout." Soft bubble and squeak is mashed potatoes that were warmed up. The judges have grandmothers. They knew.