In a bowl, mash the ripe banana until smooth.
Add rolled oats, plant-based milk, peanut butter, chia seeds (if using), vanilla extract, cinnamon, and salt. Stir well to combine.
If you prefer a sweeter taste, add maple syrup or agave nectar and mix thoroughly.
Transfer the mixture into a jar or an airtight container, seal, and refrigerate overnight (or for at least 4 hours).
In the morning, stir the oats well before eating. Enjoy cold, or microwave for 30-60 seconds if you prefer a warm breakfast.
Top with extra banana slices, peanut butter drizzle, or nuts if desired.