Fishies En Papillote
You shall have a fishy on a little dishy,
You shall have a haddock in a paper bag...

Fish En Papillote
main fish
This is a terrifically simple and clean way to prepare nice fat fish fillets.
Basically the fish is sealed along with flavouring ingredients and possibly a small amount of veg in a bag and baked quickly so that it steams in its own juices. The bag puffs up nicely during this process, so at least you can tell when the steaming is underway. The main disadvantage being that there's no way to rescue an undercooked bag, so fish is the ideal content - it being fairly difficult to disasterously undercook fish.
There seems to be no functional reason to prefer parchment or greaseproof paper parcels over tin foil, except that the crispy paper puff looks nicer if you serve it at table, and it avoids accidentally eating any bits of foil.
However, paper is harder to seal and has a tendency to burn, so you see chefs faffing about smearing their parchment with oil to protect it, and brushing beaten egg whites along the folded edges to seal the parcels like pastry.
I rather like Rick Stein's take on this which is to use a sheet of tin foil on the fishy side and cover it with parchment on the outside. That way you get the restaurant look of golden parchment with all the foolproof convenience of tin foil.
Bonus!

Rick's method:
Cut a one-foot (ish) square of both tin foil and greaseproof paper. Lay the foil on top of the paper and fold in half to make a nice crease, then open again.
Oil the foil a little if necessary, then pile your fishy product in the middle of one creased half.
Loosely fold the foil and parchment over together, then work around the edges making tight little folds about 1cm deep and 4cm long. Don't make the packet too tight - there should be room inside for expansion.
Then do the whole edge again.
Then bash the double-folded edges down with a rolling pin. You want the parcel really well sealed.

Rick recommends cooking as hot as your oven will go (Gas 9/475°F) for 15 minutes which worked perfectly for me. I see others cooking at significantly lower temperatures (Gas 4-5/350°F) for only slightly longer. Which seems unlikely to work well to me, though I can see you might need to do that if you've stuffed a whole vegetable allotment in with your fish.
In any case unless you have anything in the bag which requires a longer cooking time, the parcel is ready the instant the bag puffs up. Any longer and delicate fish will overcook.

Here are a few papillote seasoning ideas:
  • Oriental styley (ginger/rice wine/soy sauce)
  • Gremolata (lemon/garlic/parsley)
  • Italian (tomatoes/olives/herbs/chilli)

Galangal Haddock En Papillote
main fish
It was Sunday when I cooked this, so obviously no fishmonger was open. Why would they open so that people who earn money by working during the week can buy fish at the weekends when they need to eat? Ludicrous.
So I bought my fish at a Fucking Supermarket™ which meant the only fish available were some thin, bony skinless fillets of Haddock. If you can, find yourself nice fat fillets of some solid white fish, preferably with the skin still on. I would have bought Hake if there'd been any.

Serves 2

Ingredients
Method
Prepare two parcels from sheets of foil/parchment.
Preheat the oven to Gas 9 (250°C/475°F).
Mix the liquids together.
Peel the galangal and slice it lengthways into strips, use these to make a bed for the fish on one half of your paper sheets. Drizzle with a little sauce.
Place the fish fillets on top, drizzle with more sauce and decorate with shredded spring onions.
Fold up your two packets, making sure they're well sealed.
Stick in the oven for 15 minutes, or for a few after the parcels puff up.
Present the parcels at the table and let the diners open them themselves to better appreciate the gush of delicious fragrance and burn hell out of themselves on the steam.
Very mild but pleasant taste, and the fish is beautifully cooked.
As I mention this would be best with a nice fat fillet.
The galangal didn't really seem to generate much flavour, but I'd be reluctant to actually shred the galangal as I wanted the guests to be able to leave it to one side (it's a bit woody). I suppose more, thinner slices might be the solution, lining top and bottom? Maybe give it a good bash with a rolling pin to open up the fibres?