Snazzy Snapper

• 1 onion
• 425 gr snapper fillets (red)
• 120 gr swiss cheese (shredded)
• 80 ml dry wine (white)
• 65 gr saltine cracker crumbs
• 24 gr flour
• 2 gr parsley fakes
• 1 gr paprika
• 1 package four mushroom (pieces)