Ingredients:

  • ¾ cup (170g) unsalted butter, melted and cooled slightly
  • ¾ cup (150g) packed light brown sugar
  • ¼ cup (50g) granulated white sugar
  • 1 large egg
  • 1 large egg yolk
  • 1 tsp (5ml) pure vanilla extract
  • 1 ½ cups (188g) all-purpose flour
  • 1 tsp (5g) ground cinnamon
  • ½ tsp (3g) baking soda
  • ½ tsp (3g) salt
  • 3 cups (270g) old-fashioned rolled oats
  • 1 cup (170g) semi-sweet chocolate chips

Instructions:

  1. In a large bowl, whisk together the 170g melted butter, 150g brown sugar, and 50g white sugar until the mixture is smooth and no lumps remain.
  2. Add the 1 large egg, 1 large egg yolk, and 5ml vanilla extract to the butter mixture, whisking vigorously for about 60 seconds to ensure sugars are fully dissolved.
  3. In a separate medium bowl, whisk together 188g all-purpose flour, 5g ground cinnamon, 3g baking soda, and 3g salt.
  4. Gently pour the dry mixture into the wet ingredients and fold together with a spatula until just combined; do not overmix.
  5. Stir in 270g old-fashioned rolled oats and 170g semi-sweet chocolate chips until evenly distributed.
  6. Scoop rounded tablespoons of dough onto a parchment-lined baking sheet, spacing them 2 inches apart.
  7. Place the baking sheet with scooped dough in the refrigerator to chill for 30 minutes.
  8. Preheat the oven to 180°C (350°F).
  9. Bake for 9–11 minutes, or until the edges are set and lightly golden, but the centers still look slightly underbaked.
  10. Allow the cookies to cool on the pan for 5 minutes to set before transferring.