In a large mixing bowl, combine ½ cup of cooled melted butter with 1 cup of brown sugar. Blend until smooth.

Peel and mash one very ripe banana until smooth and add it to the butter-sugar mixture. Mix in 1 egg yolk and 1 teaspoon of vanilla extract.

Sift in ½ teaspoon of salt, ¾ teaspoon of baking soda, and ½ teaspoon of cinnamon. Stir until no dry streaks remain.

Gradually fold in 1 ½ cups of all-purpose flour using a spatula and mix until just combined.

Gently fold in 1 cup of chocolate chips, ensuring they are evenly distributed.

Cover the bowl with plastic wrap and refrigerate the dough for at least 1 hour.

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

Using a cookie scoop, portion the chilled dough onto the prepared baking sheets, spacing them 2 inches apart.

Transfer the baking sheets to the oven and bake for 10-12 minutes, until the edges are golden.

Let the cookies cool on the baking sheets for 2 minutes before transferring to wire racks to cool completely.