4 (4-ounce) skinless salmon fillets, 3/4 to 1 inch thick
1/4 to 1 teaspoon fine sea salt (normal table salt can be used)
1/4 cup apple jelly
2 teaspoons aged balsamic vinegar
3/4 cup julienne-cut, unpeeled, Granny Smith or other green apple (1/4 x 1-1/2-inch-long slivers)
3/4 cup julienne-cut, unpeeled Gala or other reddish apple (1/4 x 1-1/2-inch-long slivers)
1/3 cup very thin sliced and quartered leek (white and light green portion only)
Course-ground black pepper
Preheat oven to 450 F. Fold each piece of paper crosswise in half. Cut 4 half-heart shapes 7 inches longer and 4 inches wider than the fillets (the fold edges will be the centers of the hearts). Open each paper or foil heart; set aside.
Lightly sprinkle salmon with 1/4 teaspoon salt. Place each fillet near the center on one side of each heart.
Heat apple jelly over low heat or in a microwave oven just until melted. Remove from heat; stir in balsamic vinegar. Spoon mixture evenly over fillets. Toss together apples and leek. Place mixture evenly on top of fillets.
Fold opposite side of each heart up and over the fish and apple mixture. Starting at top of heart, fold edges to seal open sides by making small tight folds. Twist tip of hearts to close packets. Place packets on baking sheet. Bake in preheated oven for 8 to 12 minutes until fish flakes easily. (Carefully open packets to check doneness.)
To serve, cut packets open by slashing a large X on the top of each, then fold back paper. Transfer packets to dinner plates and serve with rice. Or, if desired, remove fish with apples from packets and place slightly on top of rice; spoon over juices. Season to taste with additional salt and the pepper.