Place bananas in food processor (they must be frozen firm) process until crumbly
Add additional ingredients. Process until smooth. You may need to scrap down sides of processor a few times. The finished product will resemble soft serve, or if you would like it firmer place in the freezer for a few minutes.
Top with items of your choice. My favorites are: pistachios, dried cherries, coconut, and whipped coconut creme (recipe here, but eliminate the bourbon and add a pinch of cardamom)
Notes
You can use the banana base for any ice cream, the coconut milk is optional and add whatever flavors you like. I love chocolate peanut butter, or chocolate mint.