Peel the ripe bananas and break them into smaller pieces.
In a blender, add the banana pieces, peanut butter, milk, honey (if using), vanilla extract, and ice cubes.
Blend on high speed until all ingredients are smooth and well combined, about 30-60 seconds.
If the smoothie is too thick, add a little more milk to reach your desired consistency and blend again.
Pour the smoothie into two glasses and enjoy immediately.
Consider adding protein powder, spinach, or chia seeds for extra nutrition, if desired.