Thaw fish, if frozen. Fold each sheet of parchment paper in half lengthwise. Then cut each sheet in a half-heart shape 6 inches longer and 2 inches wider than the fish. (The fold will be the center of the heart.)
Open each paper heart; arrange one fish fillet on the right half of each heart. Tuck under any thin edges of fish. Sprinkle fish with salt and pepper. Spoon cream cheese over the top of the fish. Top with green or red pepper and onion.
To seal, fold the left half of the paper heart over the fish, matching edges. Starting at the top of the heart, seal the package by folding the edges together in a double fold. Fold only a small section at a time to ensure a tight seal. Then twist the tip of the heart to close the package.
Place bundles on an ungreased baking sheet. Bake in a 450 degree F oven about 10 minutes or until paper puffs up and fish just begins to flake easily (carefully open the paper to check doneness). Transfer the bundles to individual plates.
To serve, cut a large X on the top of each bundle, then pull back the paper. Sprinkle fish with cilantro or parsley. Serve with lime or lemon wedges. Makes 2 servings.
Serve this Mexican-seasoned fish with breadsticks and mixed greens with avocado.