Preheat the oven to 180C Fan.
Peel the potatoes, chop them in half, then pop them into a saucepan of cold water. Season generously with salt then simmer until they are tender.
Meanwhile, heat some cooking oil in a large pan over a medium to high heat. Add the diced onion and cook until it softens.
Add in the garlic, ginger, and curry powder and cook for a couple of minutes.
Now add the butter, then when it’s melted, add in the flour, and stir well. Cook for a further minute.
Pour in the milk, stir well, and cook until it starts to thicken. Once it’s thick, taste for seasoning, it will need some salt and pepper.
Turn off the heat, then add the fish pie mix, peas, and coriander. Stir well then transfer it to an oven proof dish, leaving at least a cm gap at the top.
Once the potatoes can break easily with a knife, drain them, and leave to steam dry. Once dry, mash them until smooth, then add the butter and milk along with some salt and pepper and mix until it’s smooth.
Spoon the mashed potato over the top of the pie, then use a fork to rough it up. Bake it for about half an hour. Then dish it up, and enjoy.
