Preheat the oven to 350°F. Line a baking sheet with parchment.
In a mixing bowl, stir together the brownie mix, oil, and eggs until a thick dough forms. Fold in the peppermint bark chips and white chocolate chips until evenly distributed.
Scoop dough onto the prepared baking sheet, spacing cookies about 2 inches apart.
Bake for 10–12 minutes, until the edges are set and the centers are soft. Let cookies cool slightly on the pan before transferring to a wire rack to finish cooling.