● 50g butter, plus extra for greasing
● 6 potatoes, peeled and chopped
● Salt and freshly ground black pepper
● 2tbsp olive oil
● 1 leek, finely chopped
● 1 small fennel bulb, finely chopped
● ½tsp turmeric
● 2tbsp plain flour
● 250ml double cream
● 500g firm white fish fillets, defrosted if frozen and cut into chunks
● Grated zest of 1 lemon
● 320g pkt ready-rolled puff pastry, defrosted if frozen
● 500g frozen peas, defrosted and roughly mashed
1 Preheat the oven to 180°C (fan 160°C, gas 4). Lightly grease a large square ovenproof dish.
2 Cook the potatoes in a saucepan of boiling water for 10-12min until tender. Drain, mash and stir in the butter. Season with salt and pepper.
3 Heat the oil in a pan over a high heat. Cook the leek, fennel and turmeric for 3-4min until softened. Stir in the flour and cook for 1min. Remove from the heat. Gradually stir in the cream and 65ml water, stirring until smooth.
4 Return to the heat and cook, stirring, until the sauce is boiling and thickened. Simmer for 3min. Remove from the heat and stir in the fish and lemon zest. Season.
5 Line the dish with the pastry sheet, bringing the pastry up the sides and trimming if needed. Prick the base with a fork and line with baking paper and baking beans or uncooked rice. Bake for 10min. Remove the paper and beans and bake for a further 10min.
6 Fill the pastry case with the fish mixture, spoon over the pea mash, then top with the potato. Bake for 20-25min until golden. Serve with salad, if liked.
Don’t throw away the frilly green fronds from the top of the fennel — chop finely and stir into the pea mash before spooning into the dish in Step 6.