For Marshmallow Fluff

1. Put water, castor sugar, and corn syrup in a heavy-bottom saucepan. Bring this mixture to a boil till it reaches 115°C. Use a kitchen thermometer to track the temperature. Meanwhile, we’ll beat the egg whites.
2. Add egg whites and lemon juice together in a bowl and beat the mixture until you get fluffy egg whites.
3. Once the syrup reaches the desired temperature, add it to the whipped egg whites gradually and continue beating. Make sure to add only a little syrup at a time.
4. Now add vanilla essence to the fluff and give it a nice mix. Our marshmallow fluff is now ready. 

For Brownie

1. Put the butter, castor, and brown sugar in a bowl for the brownie and melt in the microwave. 
2. Now add curd and condensed milk to the melted butter mixture and mix it well.
3. It’s time to sift in all the remaining dry ingredients, i.e., all-purpose flour, natural cocoa powder, salt, and baking powder. Mix these until you get a thick batter.
4. To make the thick batter a bit smooth and flowy, add the milk and stir it well.
5. Lastly, add chopped dark couverture chocolate to the batter, giving it a good mix.
6. We’ll now pour the batter into a greased, lined square ring. Then pipe marshmallow fluff blobs onto the batter and make swirls using a toothpick.
7. Bake it in a preheated oven at 180°C (OTG MODE: lower rod only) for 25 – 30 minutes or until a toothpick inserted in the center comes out clean.

Our decadent marshmallow fluff swirl brownies are now ready! Serve them warm with a cup of coffee, and enjoy!