Gather all your ingredients to make the process smoother.
In a mixing bowl, combine the rolled oats, ground flaxseed, chia seeds, and a pinch of kosher salt. Stir until evenly distributed.
Pour in the milk, vanilla extract, and maple syrup or honey if using. Stir well to coat the oats.
Spoon the mixture into jars or containers, leaving space at the top for expansion.
Seal the jars and refrigerate overnight or for at least 4 hours.
In the morning, stir the oats. Enjoy them cold or warm them in the microwave. Top with your favorite fruits, nuts, or granola.