1. In a large mixing bowl, beat the softened butter, granulated sugar, and light brown sugar together with an electric mixer on medium speed until the mixture is light and fluffy, about 2-3 minutes. The color should lighten, and the texture should be airy.

2. Beat in the vanilla extract, then crack in the large egg, mixing until just combined. Scrape down the sides of the bowl to ensure everything is incorporated. Finally, add the unfed sourdough discard and mix on low speed until it’s fully blended into the butter mixture.

3. In a separate medium bowl, whisk together the all-purpose flour, baking soda, and salt. Make sure there are no lumps of baking soda.

4. With the mixer on low speed, gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined. Be careful not to overmix the dough; stop as soon as no dry streaks of flour remain.

5. Gently fold in the semi-sweet chocolate chips using a spatula. Ensure they are evenly distributed throughout the dough.

6. Cover the bowl with plastic wrap and refrigerate the dough for at least 30 minutes. Chilling helps the flavors meld and prevents the cookies from spreading too much during baking.

7. Preheat your oven to 375 F (190 C) and line a baking sheet with parchment paper. Scoop rounded tablespoons of dough and, using your hands, gently shape them into heart forms. You can make a small indentation at the top and pinch the bottom to create the point. Place them about 2 inches apart on the prepared baking sheet. If desired, press a few extra chocolate chips onto the top of each heart for a prettier finish.

8. Bake for 10-12 minutes, or until the edges are lightly golden brown and the centers are just set. The cookies might look slightly underdone in the middle, but they will continue to cook as they cool. Let them cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.