Slice ripe bananas into 1 inch pieces and store in the freezer a day ahead
Place frozen bananas into a food processor and blend on high speed. Every so often, stop the processor so you can scrape off the bananas from the side. Resume until you see the banana magically turn into the consistency of ice cream. This may take several minutes.
You can eat it as is or I prefer to put it back into the freezer for a few hours to get a little more solid.
Chocolate syrup
Whisk cocoa powder, sugar, salt, and water together in a small pot until lumps are removed.
Place the pot over medium heat and whisk continuously. Once it thickens, turn the heat to low.
Continue to whisk for another 30 seconds.
Remove from heat and stir in the vanilla.
Let the syrup cool down and pour it over the 1 ingredient banana ice cream.