I love baking salmon fillets (and other fish fillets for that matter) en papillote - it keeps the flesh super-moist, creates a sauce, reduces washing up and also seems to cut down on some of salmon's oilyness. I take a sheet of foil and top it with a smaller sheet of baking parchment. Then build the dish - you can simply put the fish in with a dot of butter, some lemon and seasoning. Or you can put a bed of spinach, chard, julienned leeks, whatever, on the bottom first, then lay the fish on top. I added some lemon and a tablespoon of Noilly Prat (white wine would be fine), then sealed the package tightly, placed on a baking tray and baked in a hot oven (200 degrees) for 20 minutes. The smell when you unwrap the parcel is divine. Serve as it is with the juices poured over, or pour the juices into a pan and boil for a minute, then stir in a spoonful of double cream or creme fraiche and some chives for a bit of indulgence. I'll leave you to guess what we did.