Preheat Oven and Prepare Pan
Preheat your oven to 350°F (175°C). Line a 9x9-inch baking pan with parchment paper, leaving overhang on the sides for easy removal, or grease the pan thoroughly. Proper preparation ensures your brownies won't stick and will be easy to slice later.
Mix Batter
In a large mixing bowl, combine the red velvet cake mix, melted butter, eggs, and vanilla extract. Stir the ingredients until they form a smooth, thick batter with no dry cake mix visible. The batter will be deeper in color than traditional brownie batter due to the red velvet mix.
Add Mix-Ins
Gently fold in the white chocolate chips and crushed Oreo cookies until they're evenly distributed throughout the batter. Don't overmix at this stage to preserve the cookie chunks and prevent the white chocolate from melting into the batter.
Transfer to Pan
Spread the batter evenly into your prepared baking pan. Use a spatula to smooth the top and ensure the batter reaches all corners for even baking.
Bake
Place the pan in the preheated oven and bake for 25-30 minutes. The brownies are done when a toothpick inserted into the center comes out with a few moist crumbs attached. Avoid overbaking as this can dry out your brownies.
Cool and Serve
Allow the brownies to cool completely in the pan on a wire rack before cutting into squares. For the cleanest cuts, refrigerate for about an hour before slicing. Serve at room temperature for the best texture and flavor.
