In a large mixing bowl, combine 1/4 cup of melted butter (or vegetable oil) with 1/2 cup of light brown sugar and 1/4 cup of mashed overripe banana. Stir well until you have a smooth mixture, ensuring that all ingredients are fully integrated.

Next, incorporate 1 egg yolk and 1 teaspoon of pure vanilla extract into the banana mixture. Use a whisk or spatula to blend these ingredients thoroughly.

Gradually sift in 1 cup of all-purpose flour, 1/2 teaspoon of baking soda, 1/4 teaspoon of ground cinnamon, and a pinch of salt. Use a spatula to fold the dry ingredients into the wet mixture gently until no streaks of flour remain.

Next, gently fold in 1/2 cup of chocolate chips into the dough, ensuring they are evenly distributed.

Set the cookie dough aside for 15 minutes to hydrate while you preheat the oven to 350°F (175°C).

Once rested, scoop tablespoon-sized amounts of dough onto the prepared cookie sheet, leaving about 2 inches of space between each scoop.

Place the baking sheet in the preheated oven and bake for 10-11 minutes, keeping an eye on them.

After baking, let the cookies cool on the baking sheet for about 5 minutes before transferring them to a wire rack.