1. Preheat oven to 350 degrees Fahrenheit. Spray a 10-inch pizza pan generously with oil spray.
2. In a medium bowl, beat eggs. Add sugar, vanilla sugar, and oil and beat until smooth.
3. Add cocoa, flour, salt, and baking powder and mix until well incorporated.
4. Carefully spread batter into prepared pizza pan.
5. Bake for 15 minutes. Allow to cool.
6. In a microwave-safe bowl or measuring cup, melt marshmallow fluff for 15–20 seconds. Spread fluff carefully on brownie.
7. Sprinkle chocolate chips, crushed graham crackers, and marshmallows on top of the fluff.
8. Place back in the oven for five minutes, until marshmallows are toasted, or place in broiler for two minutes.
9. Melt remaining chocolate chips and drizzle over the dessert pizza if desired.
10. Allow to cool for a few minutes. Slice like a pizza into eight large pieces or 16 smaller pieces.