Prep: Preheat oven to 325 F. Line 2 baking sheets with parchment paper. Set aside.
Make the dough: Cream the butter, sugars, peanut butter and vanilla.
Add in the sourdough discard and egg until no traces of yolk or sourdough remain.
Fold the dry ingredients in until no dry bits of flour remain.
Portion out the dough: Using a medium-sized (1 ½-tablespoon) cookie scoop, portion out the dough and place them on the prepared baking sheet, at least 2 inches apart to allow them to spread.
Fill a small bowl with cane sugar. Dip and coat the cookie dough balls in cane sugar.
Flatten the cookies using a fork, creating a grid pattern.
Bake: Bake the cookies for 10 to 12 minutes or until the edges are lightly browned.
Allow the cookies to cool completely on the baking sheet, for about 5 minutes. Don’t move your cookies too soon or they will break apart.
Enjoy and store: Enjoy the cookies warm, once they have set completely. These cookies get even better once they have cooled completely and their flavor has fully developed. Store leftover cookies in an airtight container for up to 1 week.
