When I moved here, I discovered colcannon and never looked back. I make it every single time I get cabbage or spinach or kale in my veg box. I often have some stashed away in the freezer for a potato emergency. Here is what I did. I fried up a diced onion until brown and then braised my shredded greens (maybe about 100g) with the fried onions while my potatoes (maybe about 500g) were boiling in salted water. Once the potatoes were done and drained I added some non-dairy/dairy milk, an unholy amount of butter, salt, pepper, and a teaspoon of mustard, and roughly mash. I then stirred in the onions and greens.

Since I had some leftover pastry in the fridge from pie I made earlier, I added some nondairy/dairy cheese to the mix and stuffed them into some pastry, brushed with some nondairy/dairy cream, and baked at 200c/400f for about 20 mins or until golden. Done and done.