Preheat and prep. Heat the oven to 350°F (175°C). Line two baking sheets with parchment paper for easy cleanup.

Mash the bananas. In a large bowl, mash the bananas with a fork until mostly smooth. A few small lumps are fine.

Whisk in wet ingredients. Add the melted butter, brown sugar, egg, and vanilla. Whisk until the mixture looks glossy and well combined.

Combine dry ingredients. In a separate bowl, whisk the flour, baking powder, baking soda, cinnamon, and salt. This helps distribute the leavening evenly.

Bring it together. Add the dry ingredients to the wet ingredients. Stir gently with a spatula until just combined. Do not overmix.

Fold in extras. If using chocolate chips or nuts, fold them in now. The dough will be soft and slightly sticky.

Chill the dough. Cover the bowl and chill for 20–30 minutes. This step helps control spread and makes the dough easier to scoop.

Scoop the cookies. Use a 1.5-tablespoon scoop or spoon to portion dough onto the baking sheets, leaving about 2 inches between cookies. If you like, sprinkle the tops with turbinado sugar for sparkle and crunch.

Bake. Bake for 10–12 minutes, until the edges are set and the tops look dry with light golden bottoms. They should still feel soft in the center.

Cool. Let the cookies rest on the sheet for 5 minutes, then move them to a wire rack to cool completely. They’ll firm up as they cool.