Fish pie is a real staple of Irish family cooking and everyone has their own way of making it. This is my version and usually results in lots of very clean plates when it comes to washing up!
Preheat the oven to 170°C (325F/Gas 3). Season the haddock, cod and salmon and place in a roasting tin with the bay leaf and milk. Poach in the oven for 10-15 minutes or until the fish flakes easily when tested with a knife.
Remove the fish from the tin and take off any remaining skin. Flake the flesh, checking for bones that might have been overlooked. Strain the leftover milk into a measuring jug until you have 600ml (1 pint). Discard the bay leaf. Increase the temperature of the oven to 180°C (350F/Gas 4).
Place the potatoes in a large pan of salted water, bring to the boil and cook for 15 minutes or until tender. Drain and return to the pan to dry out a little. Mash the potatoes and beat in half of the butter and half of the pesto. Season well.
Melt the remaining butter in a small pan and gently cook the leeks and onion for about 5 minutes. Pour in the white wine and reduce by half. Stir in the flour and cook for 1 minute, stirring constantly. Gradually pour in the reserved poaching milk and stir until you have a smooth sauce. Season and reduce the heat. Add the herbs and simmer for 3 minutes, stirring occasionally. Lastly add the prawns, flaked fish and crème fraiche and cook for 2 minutes. Be careful not to boil the mixture because the fish will break up and the sauce will go mushy.
Spoon the fish mixture into a 3 litre (5 pint) shallow ovenproof dish and dot with the remaining pesto. Top it with the flavoured mashed potato and sprinkle with the breadcrumbs. Bake in the hot oven for about 20 minutes or until the top is golden.
To serve, divide among warmed serving plates and add some broccoli to each one.