500g white fish fillets, cut into bite-sized cubes
300g prawns, peeled and cooked
800g new potatoes
1 tbsp olive oil, plus extra for drizzling
Melt the butter in a saucepan over a medium heat and cook the leek for 2-4 minutes until soft. Stir in the flour until the leek slices are all coated.
Pour in the milk and cook, stirring frequently, for a few minutes until thickened.
Stir in the dill, zest and seasoning. Add the white fish and cook for 2-3 minutes.
Remove from the heat and stir in the prawns and peas.
Pour the mixture into a 35cm rectangular roaster and leave to cool slightly.
Place the potatoes into a large saucepan of salted water and bring to the boil. Cook for 15 minutes until tender. Drain well, then leave to cool slightly. When cool enough to handle, quarter the potatoes and toss with the oil and plenty of salt and pepper.
Preheat the oven to 200˚C/180˚C fan/gas mark 6. Bake for 30-40 minutes or until the potatoes have browned and the filling is bubbling at the sides.