750ml milk

1 slice onion

2-3 sprigs of fresh parsley

1 bay leaf

a few black peppercorns

85g butter

70g plain flour

2.5ml grated lemon zest

1 egg, beaten to mix

salt and pepper

145g water biscuits, coarsely crushed

700g skinless smoked haddock or whiting fillets, finely diced

Preheat a 180 degrees Celsius/Gas 4 oven.

Bring the milk to the boil with the onion, herbs and peppercorns. Off the heat, let stand 20 minutes to infuse. Melt 70g of the butter, stir in the flour, then strain in the milk. Bring to the boil, whisking constantly, then simmer until thickened.

Remove the pan from the heat. Add the lemon zest and egg and mix well. Season with salt and pepper.

Scatter about one-third of the biscuits crumbs over the bottom of a buttered baking dish.

Cover with a layer of half the diced fish and arrange the strips of smoked fish on top.

Repeat the layers of crumbs, fish and sauce.

Scatter the remaining biscuit crumbs over the surface. Dot the top with the remaining butter.

Bake for about 35 minutes or until bubbling round the edges and lightly browned on top.

Serve hot.