Cream the sugar and butter

• In a mixer, cream the brown sugar and butter together until smooth.

Add the wet ingredients

• Add the eggs and vanilla and mix until combined.

Make the dough

• Add the salt, baking soda and sourdough starter.
• Slowly add the flour while mixing.
• Mix on medium speed for a minute or two.

Add the chocolate chips

• Add the chocolate chips and mix just until combined.

Rest the dough (optional)

• Bake right away, or let the dough ferment in the fridge for a couple of hours or overnight, up to three days.

Bake the cookies

• Preheat the oven to 350 °F (180 °C).
• Drop spoonfuls of dough onto a cookie sheet.
• Bake for 12 minutes or until lightly browned on the bottom.