Measure oats and place them into the mason jar or airtight container.
Add milk of choice, chia seeds or flax seeds, salt, and sweetener if using.
Stir well so the oats are fully coated and seeds are evenly distributed.
Seal the container with a lid and refrigerate for at least 6 hours or overnight.
In the morning, stir again and top with your favorite toppings before enjoying.