In a medium mixing bowl, combine the rolled oats and almond milk. Stir until the oats are fully submerged.
Add the mashed ripe banana and creamy peanut butter to the oat mixture.
Incorporate the honey or maple syrup, vanilla extract, ground cinnamon, and a pinch of salt. Mix well until all ingredients are thoroughly combined and the peanut butter has been evenly distributed throughout.
Portion the oat mixture into two mason jars or airtight containers. Make sure to leave a little space at the top for any toppings you may want to add.
Seal each container tightly and refrigerate overnight, or for at least 4–6 hours, which allows the oats to soak up the liquid and soften.
The next morning, take the jars out of the refrigerator. Stir the oats gently; if they feel too thick, add a splash of milk to reach your desired consistency.
Just before serving, sprinkle chopped walnuts or almonds over the top for a delightful crunch. Add sliced banana on top for a fresh touch.
Notes
Serve in clear glass jars to showcase the layers. Drizzle with honey or sprinkle cinnamon before serving.