Preheat the oven to 350°. Line two baking sheets with parchment paper.
In a mixing bowl, whisk together mashed bananas, egg, olive oil, and vanilla. Set aside.
Crush the hazelnuts with the wide side of a chef's knife blade, then roughly chop the hazelnuts a few times, leaving them somewhat chunky. Slide them into the wet ingredients.
In a food processor fitted with its steel blade, pulse the oats five or six times to begin breaking them down. Add the hazelnut flour and pulse another 5 or 6 times to combine. Add the baking powder, spice of your choice, and salt and pulse another few times just to incorporate.
Add the dry ingredients to the wet ingredients in the bowl, along with the coconut. Stir thoroughly. Leave it sit 5 to 10 minutes.
Scoop the batter onto the prepared baking sheets. Bake until the tops are light golden brown and the bottoms are lightly browned, switching the pans half-way through. (Teaspoon-sized drops will bake in about 16 minutes; larger drops will take longer.) Allow the cookies to cool on their baking sheets 5 minutes or so, them move them to a cooling rack to complete cooling.
Store airtight for up to 5 days. These also freeze nicely.