The really basic way to steam fish is to put it between two plates suspended over a pan of simmering water It's the sort of method old cookbooks describe as 'suitable for invalids' and it's hideous. It's not suitable for a cat, in my view.
So, in response to a request, I'm going to give you my basic way of doing this, which is known as 'en papillote' in France - literally 'in a paper bag'. Except that we are going to use kitchen foil or grease proof paper, which saves you going out to buy something special*.
The advantages of the method are that the fish cooks in its own juices, no nutrients are lost, flavorings are added at the start of cooking and the fish can be served in the parcel it is cooked in.
This method is suitable for whole fish and fillets.
Preheat the oven to 180°C/325°F
Cut or tear squares from your foil or paper that are large enough to hold the fish (one whole fish or fillet to each square) and form a parcel.
Lightly oil one side of the squares using a good quality olive oil and lay the fish on it. Sprinkle each with a little white wine, a pinch of salt, a few twists of pepper and any herb or spice you may be using. This could be chopped chili, garlic, dill, fennel, shallot, a little cumin perhaps. Anything, in fact, that your sense of flavor tells you will go well with your fish.
Close the parcels by folding the sides over each other and twisting the ends. It is easier to do this with grease proof paper if you wet the edges a little first.
Put the parcels on a baking tray and leave in the oven for 15-30 minutes, depending on the size of your fish. Don't worry, the timing is not critical. I once cooked this at a picnic by taping the parcels to the hot manifold of a car and closing the bonnet for 30 minutes.
Serve the fish still in its parcel. If you use foil, it's probably better to open up the parcels before you bring them to the table. With paper bags, however, let the guests open their own and enjoy the full flavored aroma that is released with the steam.
*You can buy special bags from cook shops that are perfect for this purpose. Follow the maker's instructions if you decide to use them
