This method of steaming fish "en papillote" or cooked in the bag is a fool-proof way to steam fish sucessfully every time. Simply seal the fish first, then place in a "bag" (made from folded and creased baking paper), then place in the oven to let the juices work their magic. Divine

Here's my recipe that I make for my family every other week and only takes 20 minutes

Thai Fish Fillets Steamed in a Bag (serves 4)
4 x 150g White Fish Fillets (I used Ocean Perch)
Olive Oil
Salt and pepper
Bok Choy

Marinade
1/2 red chilli with seeds removed, thinly chopped
1 clove garlic cut finely
4 spring onions, thinly chopped
1 tablespoon freshly grated ginger
1/3 cup soy sauce
1/4 cup mirin
1/2 teaspoon sesame oil
2 tablespoons brown or palm sugar
1/2 lemon juiced
Coriander 

Pre-heat oven to 200oC. Tear off 4 long sheets baking paper and set aside

Place all marinade ingredients except garlic in a bowl and mix

Rub fish fillets with a little olive oil and season with salt and pepper. Place fish in a pre-heated non stick pan (making sure pan is quite hot) and cook for 1 to 2 minutes on each side. We are just sealing the fish for a little colour, not cooking it through. Remove fish from pan and set aside
In the same pan, add a little oil and garlic and cook for a minute. Add the rest of the marinade and gently simmer until sugar has dissolved

Place two to three leaves of Bok Choy on one side of the baking paper. Place a fish portion on top. Fold over the other side of the baking paper so the edges meet at one edge, Make little folds and continue folding around each side to half-way. Pour in a quarter of the marinade and continue to fold the bag until fully sealed containg all the marinade. Place on a baking tray. Bake for 10 to 12 minutes. Serve in the bag and gently make a tear across the top. Sprinkle with coriander and serve with steamed rice