Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a mixing bowl, whisk together the flour, baking soda, and salt.

In another bowl, cream the softened butter, brown sugar, and granulated sugar until light and fluffy.

Beat in the egg and vanilla extract, then mix in the mashed mango until well combined.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Fold in any optional ingredients if using.

Drop tablespoon-sized portions of dough onto the prepared baking sheet, spacing them about 2 inches apart.

Bake in the preheated oven for 10-12 minutes, or until the edges are lightly golden.

Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.