Preheat the oven to 350F. Line an 88-inch baking dish with parchment paper, then spray with nonstick cooking spray.
Whisk together the flour, baking powder, salt and cocoa powder.
In another bowl, mix together the butter and brown sugar. Add in the egg, food coloring and vanilla.
Stir in the dry ingredients and set aside.
In another bowl, beat together the cream cheese and sugar until smooth. Beat in the vanilla. Stir in the Oreos until evenly combined.
Pour half of the red velvet brownie batter into the prepared pan. Smooth with a spatula.
Spread the cream cheese mixture over the top of the red velvet batter.
Drop the remaining red velvet batter over the top and spread evenly over the top.
Bake until a skewer comes out with only a few red velvet crumbs on it, about 25 - 30 minutes.
Cool completely before removing from the pan and cutting into squares.
