Slow Cooker Fruit, Nuts, and Spice Oatmeal

2 cups steel cut oats

2 cups diced apple

1 cup dried cranberries

½ cup slivered almonds

½ cup chopped pecans

3 cups water

1 cup milk

1 tablespoon ground cinnamon

1 teaspoon pumpkin pie spice

2 teaspoons butter

Combine the oats, apple, cranberries, almonds, pecans, water, milk, cinnamon, pumpkin pie spice, and butter in a slow cooker. Cook on Low overnight or 8 hours.