4 teaspoons salt-free Cajun seasoning mix (or your favorite)
extra-virgin olive oil
Preheat oven to 190C/375F.
Put each fish fillet in a large square of parchment paper and season with salt to taste.
Arrange the red onion and lemon on top, dividing evenly between each fish filet.
Top the red onion and lemon with the Cajun seasoning mix, or simply black pepper and a few sprigs of thyme. Top with a pat of butter and a little bit of olive oil.
Fold & crimp the parchment paper around the edges tightly in small folds to create a half moon shape. Make sure you press as you crimp and fold to seal the packets well, otherwise the steam will escape.
Arrange the packets on a baking sheet.
Bake for 12-15 minutes, or until the fish is cooked thoroughly and flakes when pricked by a fork.
To serve, cut open the packets and remove the fish to the plate using a spatula. Dress the fish with the liquid in the bottom of the bag.
I use one of my pre-made homemade seasoning mixes for this recipe, but use simply salt, pepper and thyme to flavor your fish or whatever you like. This method of cooking fish is also great for a white fish like cod.
Recipe by Thanks For The Food at http://thanksforthefood.com/trout-en-papillote/