Colcannon lives or dies on the potato you use — floury rather than waxy, and Chef Emily was specific about which varieties work and which turn to glue. The other thing worth knowing is that the milk and butter go in warm, because cold dairy into hot potato seizes it up. The cabbage or kale gets wilted separately and folded through at the end rather than boiled with the potatoes, which is why it stays green rather than grey.
Avery