Preheat your oven to 350°F and make sure your baking rake is in the middle of the oven.
In a large mixing bowl, whisk together the flour, oats, cinnamon, baking soda, and salt. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, or in a large mixing bowl using an electric mixer, mix the room temperature butter and the sugars together for 1-2 minutes or until fluffy and well-combined. Mix in the egg, then add in the vanilla extract.
Slowly add in the dry ingredients and continue mixing until just combined, making sure to scrape down the sides of the bowl as needed. Then mix in the white chocolate chips and dried cranberries until thoroughly combined.
Line large baking sheets with parchment paper or silicone baking mats and divide the dough into 14 balls and roll them into balls — they don't need to be perfectly round (see picture). Leave a bit of room between each ball of cookie dough so they have some room to spread.
Bake at 350°F (180°C) for 10-12* minutes or until the edges of the cookies are lightly browned and the top is set — I always bake mine for 11 minutes. Remove cookies from the oven and cool on a baking sheet for 5-10 minutes before transferring them to a wire rack to cool completely.
Store in an air-tight container on the counter.