Hearty winter delights 2: monastery fish

This is my version of a Russian classic which as its name indicates was first created by monks, for consumption during Lent--which in Russian Orthodoxy is rather longer, and stricter, than in Catholicism. But Lenten fare clearly doesn't mean too much mortification: like their fellow Catholic establishments in France, monasteries in Russia had a reputation for delicious home-grown and cooked food. For those of us outside monasteries, this dish can be eaten any time, and I especially like making it in winter, when the woodstove's going, for it needs double cooking.
To make monastery fish, you need fillets of some tasty white fish(I used mirror dory),one fillet per person, potatoes, one per person, herbs(I used dill and parsley but other good herbs would be tarragon or chervil), some butter, salt, pepper, a little white wine(optional), and some good chicken or vegetable stock.
First pan-fry the fillets in butter, salt and pepper, add a small splash of wine. (They only need a few minutes.) Set aside. peel the spuds, cut in half, and parboil in a little stock for a few minutes only. Cut each potato into large horizontal slices. Grease a glass or china ovenproof dish(not metal), and put in a layer of potatoes, half of what you have, to cover the bottom of the dish. Salt, pepper, sprinkle herbs, a knife-lick of butter. layer the fish on top of the potatoes, sprinkle with herbs, put the final layer of spuds on top. Salt, pepper, sprinkle of herbs, then gently douse with some more stock, so that you can see it pooling a little(only a little) at the bottom of the dish. This will steam the food gently during baking and make it meltingly tender. Cover the dish with aluminium foil, put in a moderate oven for about half an hour(Test the spuds with a sharp knife). Serve with sweet and sour caraway-seed-flavoured red cabbage, and enjoy!