To prepare the snapper: De-bone and fillet the snapper and season with salt, pepper, and lemon juice. Lay the fillets on a work surface. Place 1 spinach leaf on each fillet and top with onion, shrimp and scallop. Roll and secure with toothpicks. Cook with white wine in baking pan for 20 minutes and serve with lemon butter sauce.
Lemon Butter Sauce: Mix all ingredients together and heat in a saucepan, then pour over.