Prep: Preheat oven to 375 F. Line 3 baking sheets with parchment paper. Set aside.
Brown butter: Melt the butter in a small saucepan over medium heat. Heat the butter until it begins to smell nutty and turns the color of graham crackers, about 5 minutes. Transfer the butter to a large mixing bowl, add the spices, and allow the mixture to cool completely.
113 grams unsalted butter, 4 grams cinnamon
Stir in the sugars: Whisk in the sugars until completely incorporated. It may look a little grainy, but this is totally normal.
150 grams brown sugar, 100 grams cane sugar
Make the dough: Add in the sourdough discard, egg, oil and vanilla, whisk until the discard has completely dissolved.
56 grams oil, 1 egg, 113 grams sourdough discard, 6 grams vanilla extract
Fold in the dry ingredients. Stir the mixture using a spatula until no dry bits of flour remain.
120 grams all-purpose flour, 4 grams baking soda, 5 grams salt, 245 grams old-fashioned oats
Add mix-ins: Fold in the cranberries and chocolate chips until everything is well distributed.
100 grams dried cranberries, 100 grams white chocolate chips
Portion out the dough: Using a large cookie scoop, portion out the dough (3-tablespoon portions) and place them on the prepared baking sheet, at least 2 inches apart to allow them to spread. Flatten the cookies lightly.
Bake: Bake the baking sheets one at a time for 12 to 14 minutes or until the edges of the cookies are lightly browned, the tops of the cookies may still look wet. 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 them warm, once the cookies 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.