Peel and freeze the bananas at least a few hours in advance to ensure a creamy, thick texture.
Add frozen bananas, cacao powder, peanut butter, chia seeds, vanilla extract, plant-based milk, and optional maple syrup to a blender.
Blend on high speed, scraping down the sides if necessary, until the mixture becomes smooth and thick like soft-serve.
Adjust consistency: add a splash more milk for a thinner smoothie or a few extra frozen banana slices for a thicker bowl.
Pour the smoothie mixture into two bowls.
Add your choice of toppings: sliced fruit, granola, cacao nibs, extra peanut butter, or seeds.
Serve immediately while cold and creamy.