Preheat your oven to 350°F and line a baking sheet with parchment paper.
In a large bowl, whisk together the melted butter, brown sugar, and granulated sugar until smooth and glossy.
Add the vanilla and egg, mixing just until combined. (No need to overdo it — we want soft, chewy cookies, not tough ones.)
In a separate bowl, whisk together the flour, baking soda, and salt.
Add the dry ingredients to the wet and stir by hand until everything just comes together into a thick dough.
Fold in the chopped chocolate and about ¾ cup of crushed Oreos for that signature cookies-and-cream goodness.
Scoop about 1 tablespoon of dough and flatten it in your palm. Place a whole Oreo in the center, then top with another 1–2 tablespoons of dough. Gently press and seal the edges so the cookie is completely enclosed — no Oreo peeking out!
Roll each stuffed cookie in the remaining crushed Oreos for extra crunch and flair.
Place them on your prepared baking sheet about 3 inches apart (they spread a little — these are big cookies).
Bake for 8–10 minutes, or until the edges turn golden and the centers look just set.
Let the cookies cool on the pan for a few minutes before transferring them to a wire rack.