1. Place the water, wine, bay leaves, peppercorns, parsley, and salt into a large covered frying pan. (I use one with at least two-inch [five-centimeter] sides.) Set aside.
2. To prepare fish: Prepare 6 pieces of Gefen Parchment Paper, each large enough to fold over and enclose all sides of one piece of fish.
3. Spray a paper with Lieber’s cooking spray, and lay a fish fillet in the center. Smear the top of the fillet with mayonnaise or oil. Drizzle with lemon juice and sprinkle with onion powder and salt. Lay a sprig of parsley on top.
4. Gently fold the two sides of the paper to the center and wrap well. Fold edges under tightly. Repeat for all six slices.
5. Place the wrapped fillets into the broth in the frying pan. The water level in the pan should be about halfway up the fish, not more.
6. Cover and bring to a boil. Reduce heat and simmer for half an hour.
7. Remove poached fish from pan and allow to cool (since sitting in the broth would make it get waterlogged). Store in the fridge still wrapped.
8. Serve with homemade tartar sauce if desired.