In a large bowl, mash the ripe banana, then add almond milk and vanilla yogurt. Stir together until the mixture is well combined and creamy.
Stir in the gluten-free rolled oats, cinnamon, chia seeds, and 2 tablespoons of peanut butter until all ingredients are evenly incorporated.
Cover the bowl with a lid or plastic wrap and place it in the refrigerator for at least 4 hours or overnight.
Once set, divide the overnight oats evenly between two 12-ounce mason jars or serving containers, adding extra peanut butter and banana slices in the middle layers if desired.
Top each serving with an additional tablespoon of peanut butter, a few extra banana slices, and sprinkle extra chia seeds or chopped peanuts on top if preferred.