Preheat oven to 350 degrees F. Line a large baking sheet with a Silpat baking mat or parchment paper and set aside.
In a medium bowl, whisk together flour, baking powder, baking soda, and sea salt. Set aside.
In the bowl of a stand mixer or with a hand mixer, cream the butter and sugars together until creamy and smooth, stopping to scrape down the sides of the bowl as necessary. This will take 1 to 2 minutes.
Add the eggs and vanilla extract and beat until combined.
With the mixer off, add all of the dry ingredients. Turn the mixer on low and mix until just combined. Don’t over mix. Stir in the white chocolate chips and dried cranberries.
Form the cookie dough into balls, about 2 tablespoons of dough per cookie. Place on prepared baking sheet, about 2 inches apart.
Bake cookies for 10 to 12 minutes or until the edges are slightly golden brown. Check early to make sure you don’t over bake, every oven is different. Remove from oven and sprinkle the cookies with flaky sea salt. Let cookies cool on the baking sheet for 5 minutes. Transfer to a wire cooling rack and cool completely.
Pro tip-if your cranberries are not very plump and slightly dry, soak them in warm water for 5 minutes. Drain and dry well with paper towels.