In a mason glass jar or airtight container, combine all ingredients. Add additional milk if needed. The consistency should be somewhat liquidy (the oats will soak up the liquid overnight.
Seal the container with a lid and refrigerate overnight for 6-8 hours, allowing the oats to soak and soften.
The next day, give the oats a good stir. If the consistency is too thick, add a splash of milk.
Add your favorite toppings and enjoy!