Pat fillets dry, and sprinkle lightly with salt and pepper. Heat oil in a cast iron or oven-safe skillet over high heat. Sear cod on one side 2 to 3 minutes.
Remove from heat, and pour tequila into the pan. Swirl tequila around the fish, and quickly light liquid with a long match or lighter. Allow to flame 10 seconds.
Turn the fillets over, and sprinkle with lime juice and serrano chile. Roast at 425° for 6 to 8 minutes or until flaky and opaque. Remove from oven, and sprinkle with cilantro.
Wine note: A lovely, all-purpose wine to pair with this cod recipe is the Chateau Ste. Michelle 2004 Horse Heaven Sauvignon Blanc ($18). If you want to expand your vino repertoire, try Drylands Estate Sauvignon Blanc, 2004, Marlborough, New Zealand ($18), recommended by Michael Flynn, wine director and sommelier for Kinkead's Restaurant in Washington, D.C.