I've been making a lot of sea bass lately. Trader Joe's usually has frozen fillets of them for pretty damn cheap. I always use the same base ingredients and then there are other things I add or subtract. For two people:
Stuff I always use
2 fillets
2-4 big cloves of garlic
olive oil
a couple leaves of fresh basil
3-4 oz (about a half a package) of regular mushrooms
Preheat the oven to 425 F or so
I usually cut each garlic clove in half and quarter the shrooms (sometimes I've left them whole). Slice the basil into strips about 1/4" wide.
Put the fish in a baking dish, leaving some space on the sides and in between. Arrange the mushrooms around and in between the fish. Place the garlic and basil on top of the fish, spacing it evenly apart. Pour a lot of olive oil on top of everything, cover and cook. As many times as I've cooked it, I never made a mental note of how long it took. My wife likes her fish pretty well done but it's never been remotely dry or rubbery. I think its something like 8-12 min but you can tell when its done because you'll be able to hear it.
Other things I add:
Two thin slices of lemon on each piece of fish
ground gloves
a bay leaf for each piece
chili paste a little goes a long way
a small jar of marinated artichoke hearts packed in oil or two fresh artichoke hearts (the fresh ones are a bit of a pain in hte ass to get to and aren't as tasty (or cheap) as the ones in the jar.
and other random shit
To serve it, take your plate and put a lot of baby spinach on it. Enough that you cannot see any of the plate anymore. Cook a box of creamy parmesian risotto and put it all on top of the plates covered with spinach. Spead it out so its nice and thin (be carefull not to move the spinach around too much) and lay the fish on top of the risotto (try not to disturb the stuff you placed. Arrange the mushrooms (and artichokes) around the fish and enjoy.
If it's on sale, I'll steam about four spears of asparagus and place them on top of the fish.
From start to finish it takes only as long as the risotto (about 25-35 min or so) and it costs about $15. Cleanup is easy because you have only used a cutting board, a baking dish and a pot for the risotto.