1. Preheat the oven to 350°F and line a baking sheet with parchment paper.

2. Mash the ripe bananas in a bowl until mostly smooth.

3. In a medium bowl, whisk together the flour, baking soda, salt, and cinnamon.

4. In a large bowl, beat the softened butter, brown sugar, and granulated sugar until creamy.

5. Mix in the mashed bananas, egg yolk, and vanilla extract until combined.

6. Add the dry ingredients to the wet ingredients and stir gently until no dry streaks remain.

7. Fold in the chocolate chips.

8. Scoop the dough onto the prepared baking sheet, spacing the cookies apart evenly.

9. Add a few extra chocolate chips on top if desired.

10. Bake for 11 to 13 minutes, or until the edges are lightly golden and the centers are just set.

11. Sprinkle with flaky sea salt if using.

12. Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack.