Cut each fillet in half crosswise. Place a rosemary sprig on top of each fillet half (or sprinkle with dried rosemary). Replace the cut half on top. Wrap 1 slice of prosciutto around the fish and the rosemary. Sprinkle the fish with 1 tablespoon of the lemon juice and the black pepper. Set aside.
Preheat the grill or barbecue.
Place the fillets on the grill. Cook for 4 to 6 minutes or until the fish flakes easily when tested with a fork, turning once halfway through cooking.
Remove the rosemary sprigs before serving.
Notes
If you are preparing this as GLUTEN-FREE, just be sure to use a brand of prosciutto that is known to be GF.