1) For the milk chocolate. Combine all the ingredients in a sauce pan – condensed milk, double cream, milk chocolate, milk and corn starch, mix it well. Simmer on a low heat while mixing continously until it thickens. Set aside.
2) Repeat the above procedure for the white chocolate. Set aside.
3) For the ganarche, combine dark chocolate and double cream in a bowl and place it in a microwave for 1 minute set aside. Or use a diuble boiler to make the ganarche.
4) To assemble: Using a baking tray/dish, place one layer the graham crackers. Then spread the white chocolate sauce enough to cover the 1st layer. Then place another layer of graham crackers and spread the chocolate sauce enough to cover the 2nd layer. Continue the procedure until 4 layers.
5) Place another layer of graham crackers as the 5th layer then spread the ganarche evenly. Sprinkle with grated white chocolate on top. Refrigerate for a minimum of 4 hours before serving. Enjoy!