Instructions
Begin by preheating your oven to 200°C (400°F, Gas Mark 6), or 180°C if you're using a fan-assisted oven. This ensures that it's perfectly hot for baking the pie to a delicious golden finish. Place the peeled potatoes into a large saucepan filled with cold salted water. Slowly bring them to a boil, then reduce to a gentle simmer. Cook until the potatoes are completely tender when pierced with a fork, which should take about 15-20 minutes. Drain them thoroughly to remove all excess water. While the potatoes drain, prepare your fish filling. First, mash the potatoes smoothly with butter and a dash of milk. Season with freshly ground pepper and add salt as needed, tasting carefully to get the seasoning just right. Set this creamy mash aside. Now, melt the butter in a saucepan over medium heat. Add the sliced leeks and stir gently to coat them in the butter. Cover the pan with a lid and allow the leeks to simmer slowly for about 10 minutes, or until they become sweet and tender. This slow cooking intensifies their flavor and softens their texture beautifully. Measure your plain flour into a small bowl. Whisk in the white wine until the mixture is smooth and lump-free—this will help thicken your sauce nicely. Add the milk to the softened leeks in the saucepan and bring to a boil. Then, stir in the wine and flour mixture briskly to combine. Continue stirring until the sauce thickens to a luscious, velvety consistency. Season the sauce with salt and pepper to your taste, then add the chopped parsley for a burst of freshness. Gently fold in the salmon, haddock, and smoked haddock pieces, warming them through over the heat for about two minutes. Be careful not to overcook the fish; it only needs to be heated through at this stage. Transfer the fish and leek sauce to a large ovenproof casserole dish. Evenly scatter the hard-boiled eggs over the filling, adding a delightful texture and richness to each slice of pie. Allow the filling to cool slightly until it firms up, making it easier to layer. Spoon the creamy mashed potatoes over the fish mixture, spreading them evenly. Use a fork to gently create textured ridges on the top—this will help the cheese brown beautifully during baking. Sprinkle the grated Gruyere cheese evenly over the mashed potatoes. The cheese will melt into a golden, bubbling crust that adds a deliciously nutty flavor and delightful crispness. Place the casserole in the preheated oven and bake for 30 to 40 minutes, or until the top is lightly golden brown and the filling is bubbling around the edges. Keep an eye on it during the last few minutes to avoid burning the cheese. Once baked, let the pie rest for a few minutes before serving. This helps the layers set slightly for easier slicing. Serve warm, accompanied by seasonal vegetables or a simple green salad for a complete meal. Tips: To save time, prepare the mashed potatoes and fish sauce simultaneously. If you prefer a richer sauce, use full-fat milk. For an extra flavor boost, sprinkle a little extra parsley over the top after baking.
