Ingredients:

  • 1/2 cup (115g) unsalted butter, softened
  • 1/2 cup (125g) creamy peanut butter
  • 1/2 cup (100g) brown sugar, packed
  • 1/4 cup (50g) granulated white sugar
  • 1/4 cup (60g) sourdough discard, unfed/room temperature
  • 1 large egg, room temperature
  • 1 tsp (5ml) vanilla extract
  • 1 cup (125g) all-purpose flour
  • 1/2 tsp (3g) baking soda
  • 1/4 tsp (1.5g) salt

Instructions:

  1. Whisk the softened butter, peanut butter, brown sugar, and white sugar. Continue until the mixture is pale and fluffy Note: This incorporates air for a lighter texture.
  2. Stir in the egg, vanilla extract, and sourdough discard. Mix until the batter is smooth and unified Note: Don't overbeat here or the cookies will be too cakey.
  3. Sift in the flour, baking soda, and salt. Stir gently with a spatula just until no streaks of flour remain Note: Overmixing develops gluten, which makes cookies tough.
  4. Scoop rounded tablespoons of dough onto lined baking sheets. Space them 2 inches apart.
  5. Bake for 10–12 minutes until the edges are set and golden brown, but the centers still look slightly soft.
  6. Allow cookies to cool on the tray for 5 minutes.
  7. Move them to a wire rack to cool completely.