Peel and slice the bananas. Place the slices in a container with a lid and freeze for at least 2 hours, preferably overnight.
Once frozen, put the banana in a food processor or blender and add in the peanut butter, plant milk, agave nectar and vanilla. Process or blend for 2 to 3 minutes until you get a soft thick mixture.
Put the ice cream in a big container and freeze for at least 2 hours until for it to thicken. Once ready, serve with some more peanut butter or fruit.