Remove the bananas from the freezer and let them sit for 5 minutes at room temperature to allow them to thaw slightly (if you are not using a powerful blender such as a VItamix, thaw at room temperature for a few additional minutes).
Add the frozen bananas to a blender along with the peanut butter and follow one of the steps below depending on what type of blender you are using.
If you are using a powerful blender such as a Vitamix:Use a frozen dessert setting or blend on high, while pushing the contents of the blender down into the blades with a temper.
If you are using a regular blender: Make sure the bananas are allowed to thaw for a few additional minutes prior to blending. Blend on high, pushing/mixing the contents if possible in between blending. If you find that the contents are getting stuck, add a small amount of liquid such as your favorite non-dairy milk.
Once blended, the consistency of the ice cream should be similar to soft serve. Serve immediately or place in Freezable containers for a few hours to thicken to more of an ice cream-like consistency.