
Get ready, chocolate lovers! Mississippi mud pie features a classic Oreo crust, a moist brownie layer, creamy chocolate pudding, and fluffy whipped cream. You won't be able to stop at one slice.
Preheat oven to 350°F (180°C). Line a 9-inch (23cm) springform pan with parchment paper in the bottom and grease the sides.
Combine the crust ingredients in a small bowl. Press the mixture into the bottom and up the sides of the springform pan. Set aside.
Add the flour, cocoa powder, baking powder and salt to a medium sized bowl and set aside.
Add the oil, sugar and vanilla extract to large mixing bowl and mix together until well combined. Add the eggs and mix until well combined.
Add the dry ingredients to the wet ingredients and mix until well combined, but don’t over mix.
Pour the batter into the prepared crust and spread evenly.
Place springform pan on another larger pan to catch any butter that might seep out. Bake for 45-55 minutes, or until a toothpick comes out with a few crumbs.
When the brownie comes out of the oven, start on the pudding. This will give the brownie a chance to cool and settle before adding the pudding on top.
Add the egg yolks to a medium sized bowl, whisk together until smooth, then set aside.
Add the sugar and cornstarch to a medium saucepan and whisk together until well combined and no lumps remain.
Add the milk and whisk well to combine. Heat mixture over medium heat, whisking constantly.
Once the milk mixture beings to simmer, pour a little of the milk mixture into the egg yolks while whisking constantly, to temper the eggs. Add a little more of the hot liquid into the egg yolks, then pour the egg mixture back into the saucepan.
Whisk constantly until the mixture begins to thicken and comes to a boil. Allow to boil for 1 minute, then remove from heat and whisk in the butter, chopped chocolate, and vanilla extract. Stir until completely smooth and well combined.
Pour the filling onto the brownie and spread into an even layer. Press a piece of plastic wrap directly on top of the pudding and refrigerate about 4–6 hours or until the pie is set.
Add the heavy whipping cream, powdered sugar and vanilla extract to a large mixer bowl and whip on high speed until it reaches stiff peaks.
Remove the pie from the fridge and remove the plastic wrap. Remove the sides of the springform pan and use an offset spatula or knife to loosen it from the bottom of the pan. Transfer to a serving plate, if desired.
Spread the whipped cream evenly on top of the chocolate pudding.
To decorate, you can run a vegetable peeler along the side of the chocolate bar to create chocolate shavings, add chocolate curls, or even a dusting of cocoa powder. Refrigerate until ready to serve. Pie is best if stored covered in an air-tight container and eaten within 4-5 days.