Grind the marie biscuits into a fine powder and keep aside.
Heat the khoya on a low flame till it starts to ooze out fat. [Give it a mix now and then]
Mix in the mango pulp/puree and sugar. Keep stirring continuously and cook on a low flame. Cook this mixture till it starts to thicken and comes together [you will see it start to leave the edges of the pan once it thickens]
Remove form heat and set aside to cool.
Mix in the marie biscuit powder and knead a bit to incorporate it well. [The dough would be sticky. Don't worry about it, we shall take care of that]
Divide the burfi dough into two portions.
Mix cocoa powder to one portion [for the chocolate mango burfi].
Refrigerate the burfi mixture for an hour. [This will make it firm and easy to work with].
Place the choco burfi mix on a sheet of butter paper/parchment. Roll it out or pat it into a large circle.
Place the mango burfi portion over it and similarly pat it into a circle.
With the help of the butter paper carefully roll the prepared 'burfi circle' into a cylindrical log. Cover and seal with the same butter paper/ parchment.
Refrigerate for 2 hours.
Slice the burfi fudge and serve.
Store the remaining mango burfi fudge in the refrigerator.
You may skip the cocoa powder and make plain mango fudge too.
Since this is a khoya based dessert it needs to be stored in the refrigerator.
To give it some more flavour you may add cardamom powder and saffron while preparing the burfi mix.