If food tends to stick in your slow cooker, spritz with nonstick spray.
Combine all ingredients in a slow cooker and stir until well mixed.
Cook on low for approximately 8 hours.
Remove lid and stir. If you prefer a thicker oatmeal, turn to high and let cook, stirring occasionally, until desired thickness is reached.
Serve topped with light whipped cream, chocolate shavings, strawberries, or whatever delicious flavors you can think of.
Notes
Allow coffee to cool to room temperature or your oats will not cook evenly. In a pinch, place your coffee in the freezer for 10 minutes or make an extra strong pot and dilute with ice cubes. Decaffinated coffee will work just as well. Can sub out for water if you just want chocolate oatmeal. Any sweetener that dissolves will work here, keeping in mind that any strong flavors wont be covered 100% by the cocoa powder. If using a liquid sweetener, reduce water volume accordingly. (Nutritional estimate uses agave nectar).