In a large bowl, toss apples with lemon juice. In a small bowl, mix brown sugar, cinnamon and nutmeg; add to apple mixture and toss to coat. In a large bowl, drizzle butter over bread cubes; toss to coat., Place 2 cups bread cubes in a greased 3- or 4-qt. slow cooker. Layer with half of the apple mixture and 2 cups bread cubes. Repeat layers. Cook, covered, on low 2-3 hours or until apples are tender. Stir before serving. If desired, top with whipped cream.