Preheat oven to 350°F. Line a baking sheet with parchment paper.

In a large bowl, cream together butter, brown sugar, and granulated sugar until light and fluffy.

Add egg, vanilla, and sourdough discard. Mix until well combined.

In another bowl, whisk together flour, baking soda, and salt.

Gradually add dry ingredients to wet ingredients, mixing just until combined.

Fold in chocolate chips.

Drop spoonfuls of dough onto the baking sheet, spacing 2 inches apart.

Bake for 10–12 minutes, until edges are golden.

Let cool on the pan for 5 minutes, then transfer to a wire rack.