1. Trim and peel turnips and cut them into 1⁄2" cubes; transfer them to a medium saucepan.
2. Peel and core the apple and cut it into 1⁄2" cubes. Add apples to turnips along with raisins, butter, nutmeg, ginger, and cinnamon.
3. Add málaga or sherry, season the mixture with salt and pepper to taste, and stir to combine. Bring the turnip mixture to a boil over medium heat, reduce the heat to low, and simmer, covered, stirring occasionally, until the turnips are tender but retain their shape, about 45 minutes. Serve warm.