Adjust oven racks to upper- and lower-middle positions. Preheat the oven to 350°F (180°C) and line two baking sheets with parchment paper.

In a large bowl, using a handheld mixer or stand mixer, beat together the butter, brown sugar, and granulated sugar on medium speed until light and fluffy, about 2 minutes, scraping down the sides of the bowl as needed.

Beat in egg and vanilla extract, mixing until fully combined, about 30 seconds.

In a separate bowl, whisk together the flour, baking soda, and salt.

Reduce mixer speed to low (or stir by hand). Add flour mixture in two additions, mixing just until no streaks of flour remain. Do not overmix.

Fold in white chocolate chips and dried cranberries.

For thicker, chewier cookies, refrigerate dough for 20–30 minutes before baking.

Scoop heaping tablespoon-sized portions of dough onto the prepared baking sheets, spacing them about 2 inches apart.

Bake for 10–12 minutes, or until the edges are lightly golden and centers still look soft.

Let cookies cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.