Keep a zip-lock bag of frozen banana chunks in your freezer at all times so they're ready to make into nice cream when the mood strikes!
In a food processor, blender, or bullet, combine all ingredients. Blend until very smooth. You may need to add a splash of plant milk (coconut milk is good!) to help it blend.
Eat immediately for a soft-serve type ice cream, or put into freezer if you prefer harder ice cream that you can scoop.