Whisk the butter and sugars. In a large bowl, whisk together the melted butter, granulated sugar, and brown sugar until the mixture looks like wet sand.
Add the egg and vanilla. Whisk until fully combined and slightly smoother.
Add the dry ingredients. Add in the flour, baking soda, and salt. Fold gently until just a few streaks of flour remain, don't overmix or the cookies will turn out tough.
Fold in the mix-ins. Add the white chocolate chips and chopped freeze-dried strawberries. Fold gently just until distributed and no flour streaks remain.
Scoop and chill. Using a large cookie scoop, portion the dough into 9 to 10 balls. Refrigerate for at least 1 hour or up to overnight (overnight is best!). This step is non negotiable.
Preheat and shape. When ready to bake, preheat your oven to 350°F (180°C). Roll each dough ball gently between your palms and place on a parchment-lined baking sheet, spaced at least 2 inches apart. (See note 1.)
Bake. Bake for 9 to 12 minutes, until the edges are set and the centers still look a little underdone. That's exactly what you want. Let the cookies rest on the baking sheet for about 10 minutes to firm up.