Add all of the base ingredients to a pint-sized mason jar. Mix well to combine.
Top with a lid and place in the refrigerator overnight.
In the morning add toppings.
As a measure, I used UScup (240ml). *For GLUTEN-FREE option, use certified gluten-free oats. Oats can be eaten cold directly from the refrigerator or heated in the microwave for 30-60 seconds. Overnight oats will keep in the refrigerator for up to 5 days.