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

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

In another bowl, cream together 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.

Gradually add the dry ingredients to the wet mixture, stirring until just combined.

Fold in chocolate chips and/or nuts if using.

Drop spoonfuls of cookie 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 cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.