Heat oven to 375 degrees F.
Combine crumbs, margarine and cinnamon in small bowl until blended. Press mixture over bottom and up sides of 9-inch tart pan with removable bottom.
Bake crust in 375 degree F oven for 5 to 7 minutes or until lightly colored. Transfer tart pan to rack to cool.
Combine sugar, flour, gelatin and salt in medium-size saucepan. Whisk in milk and egg. Cook over medium heat, stirring constantly, until mixture coats back of spoon, about 3 minutes. Do not boil or mixture may curdle; remove from heat. Stir in vanilla.
Place saucepan in large bowl filled with ice cubes and water. Refrigerate until mixture mounds when dropped from spoon, about 30 minutes. Fold in whipped topping. Spoon mixture into cooled crust. Refrigerate until firm, about 2 hours.
Arrange sliced peaches in concentric circles on top of tart. Brush with melted jam. Serve immediately. Makes 10 servings.