1. Spray the inside of a 4-quart slow cooker with the cooking spray.
2. Combine the soup, water, eggs and cake mix in a medium bowl and mix according to the package directions. Pour the batter into the cooker.
3. Stir the water, brown sugar and cinnamon in a small bowl. Pour over the batter.
4. Cover and cook on HIGH for 2 hours or until a knife inserted in the center comes out clean.
5. Spoon the cake into bowls, spooning the sauce from the bottom of the cooker. Serve warm with the ice cream.
Tip: This warm, gooey dessert would be great sprinkled with crunchy candied walnuts.