Fast fish pie

Method

• step 1

  Heat 1 tbsp olive oil in a non-stick frying pan and tip in the celery and garlic. Cook over a high heat for 2 mins or until softened, then add in the tomatoes. Cook for another 3 mins until starting to burst. Stir in the tomato purée and fish, then pour over the stock or wine. Turn down the heat, simmer for 3 mins, then tip in the prawns and cook for a further 2 mins until the prawns are heated through and the fish flakes easily. Stir through the tarragon and spoon the mixture into a medium-sized oval pie dish.

• step 2

  Meanwhile, cook the potatoes in salted boiling water for 15 mins until softened. Drain and mash together with the remaining olive oil, 3 tbsp water and the spring onions. Spoon over the fish mixture and smooth all over to cover. Run a fork over the surface to create swirls, then cook under a hot grill for 10 mins until the topping is lightly browned.