Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, mash the bananas until smooth and liquid.

Stir in the vanilla extract and ground cinnamon.

Add the rolled oats and sea salt, mixing until fully incorporated into a thick dough.

Scoop 1-tablespoon portions of dough onto the prepared baking sheet.

Flatten each cookie slightly with a fork or the back of a spoon, as they will not spread during baking.

Bake for 12 to 15 minutes or until the edges are firm and slightly golden.

Remove from oven and allow to cool on the baking sheet for 5 minutes before transferring to a wire rack.