Preheat the oven to 450 degrees. Pour the boxes of salt into a large braising pot and heat in the oven until unbearably hot to the top of the hand. Meanwhile, place the veal stock in a medium saucepan over medium-low heat, and reduce to 1 cup. Add the lemon rind, capers, garlic, parsley, and pepper to taste. Keep warm in a hot-water bath to prevent further reduction. Trim the fillet, removing all traces of fat and silver skin between the muscles. Tie the roast with fine string at 1-inch intervals. Blanch the fresh grape leaves for 1 second in boiling water so they can bend easily. Cool them, then remove their stems and central rib. (Eliminate these steps if using canned leaves.) Roll the meat into the leaves, and tie at 1/4-inch intervals. Using a large measuring cup with a handle, transfer two thirds of the hot salt to a medium roasting pan. Arrange the meat on the bottom layer of salt, and immediately cover it with the reserved salt, to cover completely. Turn the oven temperature down to 400 degrees, and roast about 25 minutes. Remove the meat from the oven when it reaches an internal temperature of 110 degrees. Keep the meat wrapped in the leaves, and let rest 5 minutes. To serve, remove all strings and leaves, slice, and serve with the caper sauce and a garnish of stuffed mushrooms. Makes 6 servings. Source: "Martha Stewart Living - " S(Formatted for MC5): "by Lynn Thomas - Lynn_Thomas@prodigy.net" Per serving: 1 Calories (kcal); trace Total Fat; (1% calories from fat); trace Protein; trace Carbohydrate; 0mg Cholesterol; 284533mg Sodium Food Exchanges: 0 Grain(Starch); 0 Lean Meat; 0 Vegetable; 0 Fruit; 0 Fat; 0 Other Carbohydrates Recipe by: Recipe from Madeleine Kamman, chef and author Converted by MM_Buster v2.0n.