In the bowl of a stand mixer fitted with a paddle attachment, cream butter and brown and granulated sugar together on medium speed, beating until light and fluffy about 3 minutes. Add in egg and vanilla and mix until incorporated on low speed. Turn mixer up to medium-high and mix for 1 minute.

Scrape down the sides of the bowl if needed. Add the cornstarch, baking soda, and salt. Mix for 30 seconds then add the flour 1 cup at a time. Mix until fully incorporated.

Add the white chocolate chips and dried cranberries and gently fold in.

Drop heaping tablespoons of the dough or roll into balls onto a lined baking sheet. Chill the dough for either 2 hours in the fridge or 20-25 minutes in the freezer.

When ready to bake, preheat oven to 350 F. Spread cookie dough balls on 2 baking sheets lined with a silpat, or parchment paper, spaced 2 inches apart. Bake, reversing positions of cookie sheets halfway through, for 8-10 minutes until edges are just golden. Make sure not to over bake, the cookies will set up as they cool. Add more white chocolate chips is desired to cookies as they come out of the oven.

Remove from oven, let cool on baking sheet for 5-10 minutes, and then transfer to wire rack to finish cooling. (Store in an airtight container.)