Preparation
Preheat the oven to 200°C, fan 180°C, gas 6. Peel the sweet potatoes, then cut into chunks. Put in a saucepan and cover with cold salted water. Bring to the boil and cook for 16-18 minutes or until tender. Drain in a colander and leave to steam dry.
While the potatoes are cooking, halve the leeks lengthways and slice. Heat the oil in a separate large saucepan. Cook the leeks with a pinch of salt for 6-8 minutes until softened. Stir in the soft cheese, then gradually stir in the stock and bring up to a simmer. Put the cornflour in a small bowl and blend with 1½ tablespoons water. Stir into the creamy stock and continue to stir until thickened. Remove from the heat. Zest the lemon and add to the sauce with the juice of half the lemon for added zing and the chopped dill. Season to taste.
Cut the haddock fillets into large chunks. Stir into the sauce with the prawns and peas (adding the peas frozen ensures they keep their colour). Transfer to a 2.2 litre oven dish (about 20cm x 27cm x 6cm deep).
Mash the sweet potatoes and season. Spoon over the fish mixture, taking it to the edges of the dish. Rough up the surface with a fork to encourage crispiness. Place on a baking tray and then bake for 30-35 minutes until the top is golden and the sauce is bubbling up around the edges. Stand for 10 minutes before serving.
Get all the comfort of a classic fish pie but with a fraction of the calories thanks to a low-fat creamy sauce, fibre-rich sweet potato topping and lots of good-for-you greens.
5 of your five a day. High protein, low fat, low sat fat.