Preheat the oven to 350°F (175°C).

In a mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until smooth.

Add the sourdough starter, egg, and vanilla extract, and mix until well combined.

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

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

Fold in the chocolate chips.

Drop tablespoon-sized balls of dough onto a baking sheet lined with parchment paper, spacing them about 2 inches apart.

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

Remove from the oven and let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.