- In a bowl, combine all the ingredients except for the trout. Season with salt and pepper.
- Spread the vegetables on the shiny side of four 38-cm (15-inch) squares heavy-duty aluminum foil.
- Place the trout on top of the vegetables. Season with salt and pepper. Close to fully seal the aluminum foil. Take the papillotes anywhere with you in a cooler.
- To cook, place the papillotes over the coals or on a rack in a grill (medium heat). After 10 minutes, check for doneness of the fish, and continue cooking if necessary. Serve with Coal-Roasted Potatoes.