In a mason jar, bowl, or any airtight container, add the rolled oats, almond milk, mashed banana, and creamy peanut butter. Next, add the chia seeds, optional honey, vanilla extract, cinnamon, and a small pinch of salt.
Stir all the ingredients together thoroughly until everything is well combined and the mixture is smooth. Make sure the peanut butter is fully incorporated. Cover the container tightly with a lid or plastic wrap to keep it fresh.
Place the container in the refrigerator and let it sit overnight, or for a minimum of six hours. This chilling time is crucial, as it allows the oats and chia seeds to absorb the liquid and soften into a thick, creamy consistency.
The next morning, take the jar out of the fridge and give the oats a good stir. The mixture will be thick and creamy. Top it with fresh banana slices and chopped peanuts for a satisfying crunch before serving it chilled.