1. Preheat your oven to 375 F (190 C). Line two baking sheets with parchment paper or silicone baking mats.

2. In a large mixing bowl, using an electric mixer, cream together the softened unsalted butter, granulated sugar, and light brown sugar until the mixture is light and fluffy. This usually takes about 2-3 minutes. Scrape down the sides of the bowl as needed.

3. Beat in the vanilla extract and the large egg until well combined. Then, add the sourdough discard and mix until just incorporated. The mixture might look a little curdled, but that’s perfectly normal.

4. In a separate medium bowl, whisk together the all-purpose flour, baking soda, and salt. Make sure these dry ingredients are thoroughly mixed to ensure even distribution in the dough.

5. Gradually add the dry ingredient mixture to the wet ingredients, mixing on low speed until just combined. Be careful not to overmix the dough; stop as soon as no dry streaks of flour remain. Overmixing can lead to tough cookies.

6. Gently fold in the chocolate chips with a spatula until they are evenly distributed throughout the dough.

7. For best results, cover the bowl with plastic wrap and refrigerate the dough for at least 30 minutes. This helps the flavors develop and prevents the cookies from spreading too much during baking.

8. Drop rounded tablespoons of dough onto the prepared baking sheets, leaving about 2 inches between each cookie. Bake for 10-12 minutes, or until the edges are golden brown and the centers are still slightly soft.

9. Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely. This allows them to set up properly and prevents them from breaking.