Using a melon baller or a small spoon, remove the cores of the apples by scooping a well into middle about 3/4 of the way down. Sprinkle half of the cinnamon onto the apples and set aside.
In a bowl, combine the oats, brown sugar, remaining cinnamon, butter, and salt and mix well. Nestle the apples into a slow cooker and stuff about 1/4 cup of the mixture into each of the apple wells.
Place the lid on the slow cooker and set it to high for 1-1/2 - 2 hours or until the apples are soft.
Allow the apples to cool slightly then serve with vanilla ice cream.
