Rinse the fish and pat dry. Put the
flour on a plate and season it with salt and pepper. Dredge the
fillets in the flour, patting to remove excess.
In a small bowl, combine the
garlic, wine, lime juice and butter, then set aside.
Heat the oil in a 10- to 12-inch
frying pan over medium-high heat. Add the fillets without
overlapping (you may need to cook in 2 batches). Cook until
golden on the bottom, about 3 minutes. Turn the fillets over and
cook until opaque through the thickest part, 1 to 2 minutes
Transfer the fish to a platter
and keep warm (cover with foil or place in a 200°F oven).
Add the wine mixture to pan and
boil, scraping up cooked bits, until reduced by half, 2 to 3
minutes. Stir in the onions and heat on low about 30 seconds.
Pour the sauce over the fish and