Prepare the cherries. If using fresh cherries, remove the pits and either chop them or leave them whole. If using frozen cherries, I still recommend giving them a quick check - even “pitted” cherries sometimes sneak one through.
Mix the dry ingredients. Add the rolled oats, cinnamon, ground flaxseed, and chia seeds to a 16-ounce mason jar. Stir them together first so everything is evenly distributed before adding the liquid.
Add the liquid ingredients. Pour in the almond milk, vanilla extract, and maple syrup. Stir well, making sure the oats are fully covered in liquid - this is key for softening properly overnight.
Add the cherries. Place the cherries on top of the oats. As they thaw and soak, their juices will release into the oats, adding natural cherry flavor.
Refrigerate. Cover the jar with a lid and refrigerate for at least 6 hours or overnight.
Stir and adjust in the morning. In the morning, give the oats a good stir. Add a splash of milk if needed to loosen the texture, and taste to see if you want a little extra sweetness.