Preheat the oven to 375 degrees Fahrenheit and line two large baking sheets with parchment paper or grease lightly with baking spray.
In a large mixing bowl, beat the Snickerdoodle cookie mix, large egg, softened butter, and sour cream with a hand or stand mixer for 2-3 minutes or until thoroughly combined.
Fold in the white chocolate chips and dried cranberries until evenly distributed.
Using a 1 ½ inch cookie scoop, scoop out dough and form into even balls. Place them on the prepared baking sheets with 1 inch between each cookie.
Bake for 8-13 minutes or until the edges get golden brown. Do not overbake.
Remove from the oven and cool for 5 minutes before removing to a cooling rack or serving warm.