Preheat your oven to 350°F (175°C).
In a bowl, cream together the softened butter, brown sugar, and granulated sugar.
Add the active sourdough starter and mix until well combined.
Stir in the egg and vanilla extract.
In a separate bowl, whisk together flour, baking soda, and salt.
Gradually add the dry ingredients to the wet mixture, stirring until combined.
Fold in the chocolate chips until evenly distributed.
Drop spoonfuls of dough onto a lined baking sheet, spacing them apart.
Bake in the preheated oven for 10-12 minutes until golden brown.
Remove from oven and let cool on the baking sheet for a few minutes before transferring to a wire rack.