How to Make It
Season the fish medallions well with salt and pepper. Season the flour with salt and pepper and place it in a shallow bowl or on a plate. Dredge each piece of fish in the flour, patting off the excess.
In a large skillet, heat 1/4 cup of the olive oil over high heat until smoking. Working in batches if necessary to avoid overcrowding the pan, cook the fish in the hot oil, turning once to brown both sides evenly and cook through, about 4 minutes per side. Remove the fish to a plate lined with paper towels. When all of the fish is done, keep warm.
Add the wine, turmeric, lemon juice, and caperberries to the skillet. Swirl over high heat for 2 minutes. Season the sauce with salt and pepper and add the lemon segments, preserved lemons and parsley and swirl them over high heat for 1 minute. Add the remaining 1/4 cup of olive oil and swirl again.
Transfer the fish to warmed plates. Spoon the sauce over the fish, garnish with the remaining parsley and serve immediately.