1) Preheat oven to 190 degrees C. Coat a large cast iron pan with a nonstick butter spray.
2) Rinse fish and pat dry; place on the prepared baking sheet. Season each fillet with salt, cracked pepper, lime zest and lime juice.
3) Add fish to the pan, place a pat of butter on each fillet and cook in the oven for 8 to 12 minutes.
4) Serve immediately.