I don't really have a "recipe" per se . . . .it's just a really easy way to cook most any type of fish-salmon, mahi mahi, tilapia . . .
I take a big sheet of foil on a cookie sheet-put an entire bag o spinach (it REALLY cooks down-it's amazing!), some tomatoes, or onions or zucchini, whatever you like . . . .place the fish on top and drizzle just a bit of low sodium soy sauce on the spinach. Add some of your favorite seasonings or some lemon. Put another sheet of foil on top and seal the edges-bake around 350 or so until it smells really good. About 30-40 min.
I tend to buy the pre-marinated mahi mahi or tuna steaks at TJs-just add a fat serving for the olive oil that in there.
Tastes great and best of all-you just toss the foil. I'm lazy like that. Plus the fish is more steamed than baked and it's really tender and flaky.