Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a large bowl, cream together the softened butter, brown sugar, and granulated sugar until smooth.
Add the sourdough starter, egg, and vanilla extract to the mixture and blend well.
In a separate bowl, whisk together the flour, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Fold in the chocolate chips evenly throughout the dough.
Using a cookie scoop, drop dough balls 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.
Remove from the oven and let the cookies cool on the baking sheet for 5 minutes before transferring to a wire rack.
Enjoy your freshly baked sourdough chocolate chip cookies!