Preheat oven to 375°.
To prepare croutons, slice cake crossways into 8 (1/2-inch) slices; reserve remaining cake for another use. Cut each slice diagonally into 2 pieces. Place cake pieces on a baking sheet. Bake at 375° for 8 minutes or until lightly browned, turning after 4 minutes. Cool completely on a wire rack.
To prepare soup, combine cider and next 8 ingredients (cider through cinnamon) in a large Dutch oven; bring to a boil. Reduce heat to medium-low; simmer, uncovered, 30 minutes or until apples are very tender. Remove cinnamon stick with a slotted spoon; discard.
Place half of apple mixture in a blender or food processor; let stand 5 minutes. Cover tightly; process until smooth. Pour pureed apple mixture into a large bowl. Repeat procedure with remaining apple mixture.
Place pureed mixture in pan; stir in half-and-half. Cook over low heat 5 minutes or until heated, stirring occasionally.