Preheat oven to 400 degrees. Line muffin pan with baking cups. In a medium bowl, add flour, sugar, baking powder, cinnamon and salt; combine well. In a separate bowl, add apple cider, oil and egg and mix well with hand mixer. Add combined dry ingredients and stir just until moistened; batter will be lumpy. Add apples and stir. Fill baking cups 2/3 full with batter. Bake at 400 degrees for 15-18 minutes or until toothpick inserted in center comes out clean. If serving warm, let cool for a minute or two and then serve.