1Grease a 9x9-inch square pan. Melt 1/2 cup butter in a saucepan over low heat, and stir in cocoa mix, vanilla extract, and egg. Whisk together until the mixture thickens, about 1 minute (do not boil); remove from heat and stir in graham cracker crumbs, 1 cup coconut, and walnuts. Mix well, and press into the bottom of the prepared pan. Chill the crust for about 1 hour.
2Place the cream cheese into a mixing bowl, and beat with an electric mixer until smooth and fluffy. Beat in the milk, vanilla pudding mix, and confectioners' sugar to make a spreadable, creamy mixture. If mixture is too stiff to spread easily, add more milk, 1/2 teaspoon at a time. Spread the filling in an even layer over the crust, and return to refrigerator. Chill until firm, about 1 hour.
3Melt milk chocolate and 1 tablespoon of butter in a saucepan over very low heat, stirring constantly until the mixture is smooth and well combined. Spread the topping evenly over the vanilla layer, and refrigerate about 1/2 hour, until the topping is firm but not hard. Cut into bars, then return to refrigerator to finish chilling, at least 1/2 hour more. Serve cold.