Preheat oven to 350°F (177°C). Line a large baking sheet with a Silpat or parchment paper and set aside.

In a medium bowl, whisk together 3 cups all-purpose flour, 1 teaspoon baking powder, 1 teaspoon baking soda, and 1 teaspoon sea salt. Set aside.

In the bowl of a stand mixer or a large bowl with a hand mixer, combine 1 cup unsalted butter (cool room temperature), 1 cup packed light brown sugar, and 1 cup granulated sugar. Cream on medium speed until light and smooth, about 1–2 minutes, scraping down the sides of the bowl as needed.

Add 2 large eggs and 2 teaspoons pure vanilla extract; beat until fully combined and smooth, scraping the bowl once more.

With the mixer off, add the dry ingredient mixture to the wet ingredients. Turn the mixer to low and mix just until combined and no dry streaks remain. Do not overmix.

Using a spatula, fold in 1 cup white chocolate chips and 1 cup dried cranberries until evenly distributed.

Portion the dough into balls of about 2 tablespoons each. Place the dough balls on the prepared baking sheet about 2 inches apart.

Bake for 10–12 minutes, until the cookie edges are slightly golden. Begin checking at 10 minutes to avoid overbaking.

Remove the baking sheet from the oven and immediately sprinkle the warm cookies with flaky sea salt. Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.