If preparing indoors, preheat oven to 400 degrees.

Tear off 4 sheets of aluminum foil into sections large enough to fold over filets, with another couple of inches on each side to seal. Place a filet slightly off center on each sheet and add 3 lemon slices and 2 lime slices on top of each.  Top each filet with ¼ of the cilantro and jalapeno pepper. Top with 1 T. of butter and sprinkle with salt and pepper, to taste.

To seal packet, fold aluminum foil in half over the ingredients. Fold the 3 open sides, one at a time, over several times to seal the packet completely. The goal is to seal the packet tight enough to hold in the steam, but allow enough room for the air to expand.

Place foil packet in preheated oven for 15 minutes, or place on hot grill over medium, direct heat and cook for approximately 8 - 10 minutes. Add a couple minutes to your cooking time if starting with frozen filets.

To serve, open the foil packets, carefully avoiding the hot steam. Discard lemon and lime slices. Transfer filets to plates (if desired) or leave inside foil packets. Top with spicy peach salsa (if desired) and serve.