In a powerful blender or processor add in the chopped bananas. Addin the blackberries and vanilla. Processuntil combined.
You will need to use a tamper to ensure it blends evenly or a silicone spatula to scrape the sides.
This can take anywhere from 5-15 minutes.
Enjoy immediately as soft-serv ice cream (or place into a lined dish and freeze for thirty minutes.). Or, place in the freezer for 4-5 hours for a firmer ice cream consistency.
Notes
You can easily sub in frozen blackberries for the fresh.
However, you may need to pause and scrape down the sides a bit more depending on what machine you're using!
To make it easier on your blender, chop the frozen bananas into chunks before using them. Likewise, make sure the bananas are completely frozen before using them.
Failure to do this will result in smoothie-like consistency and not ice cream.
Do not add liquid to make the process faster. This will ruin the consistency. Be patient, scape down the sides frequently, and keep going. Depending on your machine it can take anywhere from 3-10 minutes of scraping and blending.
Top with drizzled almond butter if you're feeling extra indulgent!