In a large jar or airtight container, mix rolled oats, unsweetened almond milk, vanilla Greek yogurt, chia seeds, maple syrup, vanilla extract, and mashed ripe banana until well combined.

Seal the container tightly and chill in the refrigerator for at least 4 to 6 hours or ideally overnight.

In the morning, stir the mixture to ensure well incorporation, adding a splash of almond milk if a thinner consistency is preferred.

Crush graham crackers and sprinkle on top of the oats.

Add additional banana slices and optional whipped topping before serving.