Preheat the oven to 350°F (175°C). Line two baking sheets with parchment paper.

Add the softened butter, granulated sugar, and light brown sugar to a large mixing bowl.

Using a stand mixer or hand mixer, beat for approximately 2–3 minutes until the mixture becomes lighter and fluffy.

Add the egg and mix until incorporated.

Add the mashed ripe banana and vanilla. Mix until evenly combined. The mixture may look slightly softer than traditional cookie dough because of the moisture from the banana.

In a separate bowl, whisk together the all-purpose flour, cinnamon, baking soda, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, mixing on low speed just until a soft dough forms. Avoid overmixing.

Scoop approximately 2 tablespoons of dough per cookie onto the prepared baking sheets, leaving about 2 inches between each portion.

Bake the Banana Bread Cookies for 10–12 minutes, or until the edges are lightly golden and the tops look set and matte.

Remove the baking sheets from the oven. Allow the cookies to rest on the pans for approximately 5 minutes.

Transfer the cookies to a wire rack and let them cool completely.