Carefully remove rinds from orange and lemon using a vegetable peeler, making sure to avoid white pith; discard orange and lemon.
Place rinds, plums, juice, Marsala, and cinnamon in an electric slow cooker; stir to combine. Cover and cook on low 4 hours or until plums are very tender. Discard rinds and cinnamon stick. Cover and chill plum mixture overnight. Serve at room temperature with Yogurt Cream.
Note: Nutritional totals include Yogurt Cream.