Preheat the oven to 350℉/180℃ and line a baking tray with parchment paper. Melt the butter and as it cools prep the rest of the ingredients.
3/4 cups unsalted butter
In a bowl, add the flour, oats, baking soda, baking powder, cornstarch, cinnamon, and salt. Stir to combine and set aside.
1 1/2 cups all-purpose flour, 1 3/4 cups rolled oats, 3/4 tsp baking soda, 1/2 tsp baking powder, 1/4 tsp cinnamon, 1/4 tsp salt, 1 tsp cornstarch
In another bowl, add the melted and slightly cooled butter, brown sugar, and white sugar. Whisk for 2-3 minutes until well combined.
1/3 cup dark brown sugar, 1/2 cup white sugar, 3/4 cups unsalted butter
Add in the egg, egg yolk, and vanilla. Continue whisking until combined, scraping the bowl as needed.
1 large egg, 1 large egg yolk, 1 tbsp vanilla
Mix in the dry ingredients gently with a spatula just until a soft cookie dough forms. Do not over-mix!
Add in the dried cranberries and white chocolate. Mix in a few times, evenly distributing the add-ins amongst the cookie dough.
3/4 cups dried cranberries, 1/2 cup white chocolate chips
Scoop 6 cookies at a time per tray, spacing them evenly from one another. Add extra chocolate and dried cranberries on top (optional).
Bake for 15-18 minutes, or until the edges are a golden brown and the middles are still slightly puffy. Allow to cool, and enjoy!