Cream your butter and sugars in a stand mixer until light and fluffy.
Add in your eggs, sourdough starter, and vanilla. Mix well.
In a medium mixing bowl, mix together your flour, baking soda, baking powder, and salt. Slowly add in to your butter and sugar mixture. Mix until well combined.
Fold in your chocolate chips, nuts, or whatever add ins your prefer.
Chill the dough in the fridge for about an hour or up to 24 hours for a longer ferment. Make sure to cover with plastic wrap to prevent the dough from drying out.
Preheat your oven to 375 degrees.
While the oven is preheating, line a baking pan with a silicon baking mat or parchment paper.
Scoop out the cookie dough using a large cookie scoop and drop onto the baking pan, spacing them out about 2 inches apart.
Place in the oven and bake for 10-12 minutes or until the edges turn a nice golden brown. Remove from the oven and allow to sit for one minute before transferring them to a wire rack to cool.
