Add apples, water and salt to slow cooker. Stir and cover. Cook on high about 2 hours or low about 5 hours until tender.
Leave chunky, or puree with an immersion blender for smooth sauce. Taste for sweetness and add sugar as needed. Dust with apple pie spice.
Serve warm or chilled. Great alongside pork and chicken or stirred into your morning oatmeal or yogurt.
Variation: Use half apples and half pears for a wonderful apple-pear sauce.