Combine all of the base ingredients into the mason jar (or sealable container). Stir the ingredients well to combine. Place mason jars in the fridge overnight to allow the oats to absorb moisture. You can leave the oats up to 5 days in the fridge.
The next day for breakfast, mix in your favorite toppings.
Repeat for second breakfast, elevenses, afternoon tea, or all of the above! Enjoy adventurer!