Mix The Brown Sugar, Cinnamon, And Nutmeg Together In A Bowl. Add The Apples And Cranberries, Tossing To Coat Evenly With The Sugar Mixture. Pour Into A Slow Cooker. Top With Butter Pieces. Mix The Oatmeal Together With The Water, Apple Juice, Cranberry Juice, And Salt In A Bowl, And Pour Over The Apple Mixture In The Slow Cooker. Do Not Stir. Cover, And Cook On Low For 8 Hours. Stir Before Serving. Spoon Into Bowls And Top With Candied Walnuts, If Desired.