Wrapping up a week of food (which I noticed also happened to turn into a near-week of grilling!), this is another recipe that is really just a method, and completely flexible.
At some point, we'd like to try a little aquaponics and raise our own tilapia, so I've been experimenting with different ways of cooking it in anticipation of that far-future dream. Any white fish will do in this recipe, though, and I've also loved it with fresh-caught trout. I imagine bass would taste great this way as well!
To make these little packets, I use aluminum foil, and just layer on a base of aromatic things, followed by the fish, and topped with a marinade/sauce of some sort. I can imagine all kinds of variations, so just use what you have readily available. Here's the combination we most recently enjoyed:
Base: thinly-sliced yellow onion, thinly-sliced fresh ginger, and a few sprigs of thyme.
Fish: Tilapia fillets
Sauce: A couple Tablespoons organic soy sauce whisked with a little black pepper, a little sugar, and a little oyster sauce. Poured over the fish, and then topped with a couple lemon slices.
I put one fish per packet, and seal them up well on the sides and top (leaving an air pocket inside for the steaming to occur) by folding over and crimping the foil with my hands. They only take about 10 minutes on the grill. If you prefer, you could skip the foil and use a stovetop steamer to cook them. Using a whole fish instead of only the fillet works wonderfully, too.
When the packets are opened up just before eating, the steam releases a beautiful aroma, which I feel really adds to the enjoyment of the meal.