The filling for this fish pie is a tasty blend of spinach, salmon, and cod. Instead of putting a classic mash on top, I’ve used quickly crushed potatoes, drizzled with olive oil to make them crunchy.
Serves 6
Special equipment
2-quart (1.7–2 liter) baking dish, about 10 x 7in (25 x 18cm) and 3in (7.5cm) deep
5 tbsp (75 g) butter, plus extra for greasing
1 large leek, trimmed and cut into 1⁄4in (5mm) thick slices
1⁄2 cup (50 g) plain flour
21⁄2 cups (600 ml) hot, full-fat milk
11⁄2 tbsp chopped fresh dill
finely grated zest of 1⁄2 lemon
salt and freshly ground black pepper
14 oz (400 g) cod fillet, skinned and cut into 1in (2.5cm) cubes (see box)
14 oz (400 g) salmon fillet, skinned and cut into 1in (2.5cm) cubes
7 oz (200 g) fresh spinach
For the topping
13⁄4 lb (800 g) new potatoes, such as baby reds, scrubbed
2 tbsp olive oil, plus 2 tsp for drizzling
1. Grease the baking dish with butter. Melt 4 tablespoons (50 g) of the butter in a large pan over medium heat. Add the leek and fry for 3 minutes or until softened but not browned. Stir in the flour and cook, stirring, for 1–2 minutes. Remove from the heat and gradually pour in the hot milk. Return to medium heat and stir until boiling, thickened, and smooth. Stir in the dill, lemon zest, and some salt and pepper. Add the cod and salmon to the sauce. Cook over low heat for 2 minutes, stirring gently twice, just to start cooking the fish. (See Make a smooth, creamy filling.)
2. Pour the fish mixture into the buttered baking dish and set aside to cool (see Let the filling cool down). You can prepare up to this point 1 day ahead and refrigerate overnight.
3. Melt the remaining butter in a large, nonstick, deep-sided frying pan or sauté pan over medium heat. Add the spinach and cook, stirring, for 11⁄2–2 minutes or until it wilts. Drain thoroughly in a colander, pressing down with the back of a wooden spoon to extract excess moisture. Roughly chop and set aside. Preheat the oven to 400ºF (200ºC).
4. Meanwhile, make the topping: put the potatoes in a large pan of cold salted water and bring to a boil. Cover and simmer for about 15 minutes or until tender. Drain well. Return the potatoes to the pan and, using a fork, break up the potatoes into rough, chunky pieces. (See Make a crispy topping.) Stir in the olive oil and some salt and pepper.
5. Scatter the spinach on top of the cooled fish mixture, then spoon the potatoes over the spinach layer (see Carefully add the topping). Drizzle the remaining 2 teaspoons of oil over the potatoes and bake for 30–40 minutes or until the pie is bubbling at the edges and the topping is golden and crispy.
FISH PIE WITH CRUSHED POTATO TOPPING
KEYS TO PERFECTION
Make a smooth, creamy filling
1 The leek should look wilted before you stir in the flour. However, you don’t need to cook it completely, as it will finish cooking in the sauce. Stir the flour constantly for 1–2 minutes, making sure it is combined thoroughly with the butter. Don’t let the butter or flour brown. You’re aiming for a pale gold paste, or “roux.”
2 I like to add hot milk when making a white sauce, as I find it blends into the roux more easily than cold milk and helps to prevent the sauce from turning lumpy. Bring the milk to a gentle simmer, then remove it from the heat. If you keep it simmering for too long, it will start to reduce in the pan. Add it gradually to the roux, stirring continuously.
3 After adding the dill, lemon rind, and seasoning, add the fish to the sauce. Don’t stir too much, or the fish may start to break up; you want to keep it in chunky pieces. Just give a couple of gentle turns using a wooden spoon so the fish is well coated with the white sauce.
Let the filling cool down
Let the fish and sauce cool in the baking dish. This will provide a firmer base for when you spoon the potatoes over the top, so they won’t sink in. Spoon the spinach over the sauce before adding the topping. The spinach must be well drained so the sauce doesn’t get watery.
Make a crispy topping
1 Put the whole potatoes in a pan of cold water (if very large, cut them in half) and start the timing once the water comes to the boil. Reduce the heat slightly and let the water simmer gently. They will take about 15 minutes to cook. To test if the potatoes are done, insert the tip of a sharp knife; it should go in easily.
2 To crush the potatoes, use a fork to break each one into several chunky pieces. You don’t want to break them down too much, and they don’t need to be completely uniform in size. By crushing them the oil will be absorbed into the potato pieces, which will improve their flavor and make them golden when baked.
Carefully add the topping
Spoon the potatoes loosely over the top of the filling, rather than packing them down, so the broken edges can become crisp.
Cod has a delicate flavor and, although it has a soft and flaky texture, if handled lightly it’s still dense enough to work well and not break up in a fish pie. As when buying any fish, try to choose cod that has been responsibly sourced. Look for the MSC (Marine Stewardship Council) ecolabel, which means the fish has come from a sustainable fishery.