Marshmallow Swirled Oreo Brownies

1.Preheat oven to 325 degrees. Line an 8x8 inch inch baking dish with parchment paper, leaving about a 1 to 2 inch over hang. Set baking dish aside.
2.In a small bowl sift flour, cocoa powder, and salt and mix well.
3.In a large bowl, melt chocolate and butter together in the microwave at 20 second intervals, stirring in between each heat session. Chocolate and butter should be completely melted and smooth.
4.Add in sugar and mix thoroughly. Batter will be slightly gritty. Add in egg, thoroughly mixing then add vanilla extract and mix.
5.Slowly add in dry ingredients, folding them into the batter. You don't want to mix vigorously, just fold the batter until all the dry ingredients are incorporated. Brownie batter will be thick.
6.Pour about half the brownie batter into the bottom of your baking dish. Evenly smooth it out so it cover the bottom of the dish and creates a thin layer. Next, place Oreo cookies over the brownie batter, placing them side by side to cover the brownie layer. Spoon half of the marshmallow topping over the Oreos and batter.
7.Pour the rest of the brownie batter over the Oreo cookie and marshmallow layer. Smooth it out until it covers everything. Spoon marshmallow topping in thick lines over the brownie batter. Using a butter knife, swirl the marshmallow around in different directions to create a marbled look.
8.Bake in the oven for about 40 minutes. Brownies are done when a tester inserted into the center comes out clean. Since there are cookies in the center of these brownies you may have some cookie on your tester.
9.Allow brownies to cool completely before serving, about 30 minutes or so. When ready to serve lift up sides of the parchment paper and lay brownies on a clean, flat surface. Using a sharp kitchen knife cut brownies into squares and serve. Any leftovers should be stored in an airtight container.