Lightly oil the slow cooker to keep the oats from sticking.
Add the oats, water, and salt to the slow cooker and cook for 5 hours on low. I use a smart plug to schedule the slow cooker to turn on at 1:30am and turn off at 6:30am
In the morning, add the smashed banana, brown sugar, vanilla, and cinnamon.
Stir to combine and serve. Add chocolate chips or walnuts for a delicious topping.