Pulse freeze-dried strawberries in a food processor or blender until they become a fine powder. Roughly chop Oreos into quarters - you want visible chunks, not crumbs. Set both aside.

In a medium bowl, whisk together flour, cornstarch, baking powder, salt, and strawberry powder until evenly combined. The mixture should look pale pink with no streaks of white.

In a large bowl with a mixer, beat softened butter, cream cheese, and sugar on medium-high speed until light and fluffy, about 3 minutes. Scrape down the bowl halfway through. The mixture should look pale and hold soft peaks.

Beat in the egg and vanilla until fully incorporated, about 1 minute. The mixture may look slightly curdled at first but will smooth out.

Add the dry ingredients and mix on low speed just until no flour streaks remain, about 30 seconds. Do not overmix. The dough will be thick and sticky.

Using a sturdy spoon or spatula, fold in the chopped Oreos and white chocolate chips (if using) until evenly distributed. Cover dough and chill for 15 minutes while you preheat the oven to 350F.

Line two baking sheets with parchment. Scoop 2-tablespoon mounds of dough, spacing them 2 inches apart. Bake one sheet at a time for 11-13 minutes until the edges look set and the tops are just barely golden. The centers will look slightly underdone - this is correct.

Let cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely. They will firm up as they cool and develop that perfect soft-yet-chewy texture.