Heat oven to 350 degrees. Lightly grease the bottom and sides of a 9-inch round cake or pie pan.
In a medium bowl, sift together the flour, sugar, cocoa powder, baking powder, and salt. Add in both kinds of chocolate chips. Whisk until blended.
In a separate bowl, mix together the oil, eggs, and extract with a fork until just blended.
Pour the liquid over the flour mixture and mix with a rubber spatula until just blended. The batter will be kind of dry, don’t worry. Stir in the Oreos.
Scrape the mixture in to the pan and spread evenly. You might have to press the mixture in to the sides if you are having trouble spreading with a spatula.
Bake for 20-25 minutes or until a toothpick or cake tester inserted in to the center comes out with only a few gooey pieces clinging to it. Transfer the baking dish to a cooling rack and let cool.
Cut into wedges. If you want to-melt white chocolate and drizzle over the brownie wedges.