Combine all the dry ingredients in a large mixing bowl and set aside.
Mash the bananas in a separate bowl until smooth. Stir in the tahini and syrup and beat vigorously until everything is combined (you don't want large chunks of tahini!).
Pour the wet ingredients to the dry and stir until well mixed and all the ingredients are coated.
Separate the mixture onto two baking sheets, and bake for 30 - 35 minutes, until the granola is starting to brown. I recommend stirring and flipping it every 10 minutes to ensure even cooking.
Let cool completely then transfer to an airtight container. Store in a cool, dry place for two weeks.