Prepare the brownie mix in a medium to large bowl per the instructions listed on the box.

Place parchment paper in the bottom of a 9x9 pan, spray with cooking spray, pour in the batter, and bake. Follow the instructions on the box for the correct temperature and time.

Once baked, allow the brownies to completely cool and come to room temperature. They should be cool to the touch when ready.

Using a large spoon, lightly press down on the brownie to compact it down slightly.

Heat oven to 350 degrees Fahrenheit.

To start the filling, place the cream cheese and sugar into a mixing bowl. The cream cheese should be at room temperature.

Beat until smooth and creamy.You can use an electric mixer or mix it by hand with a whisk.

Add in the eggs and vanilla extract.

Once well combined, add in the marshmallow fluff and mix one final time.

Pour over the brownie and spread an even layer.

Using a spoon, drizzle the Nutella evenly on the cheesecake.

Take a toothpick and swirl around the Nutella into the cheesecake.

Bake bars for 20 minutes.

Once the 20 minutes are up, without opening the oven door, reduce the heat to 200 degrees and bake for an additional 30 minutes.

Once finished baking, turn the oven off and leave the cheesecake inside for 10 minutes.

Remove and allow the cheesecake to come to room temperature.

Once at room temperature, cover the cheesecake with plastic wrap and place in the refrigerator for a minimum of 3 hours.

Once chilled, take the cheesecake out and cut into 12 squares.

Serve with fresh fruit or enjoy it just as it is.