Line a 8 by 8 baking dish with parchment paper. Infuse saffron in warm milk. Let stand.
If using fresh mango, add mango chunks to a blender jar and grind to a smooth paste. If needed, strain the pulp.
To a large non-stick pan (I used 12 inch), add the mango puree, powdered sugar and milk powder.
Using a spatula, mix very well, until you see no white milk powder or sugar.
Set the pan on a low flame stovetop. Cook on low heat for 4-5 minutes, keep stirring with a spatula. As the mixture heats up, the sugar will release its moisture and the mixture will be easier to stir and will feel soft. Keep on scraping the sides of pan and mixing in, however if the mixture on sides becomes too dry, leave it.
Add saffron soaked in milk. Continue to cook.
In about 8-10 minutes, you will see that the burfi mixture starts leaving the sides of the pan and clumping around the spatula. It won't be sticky and you will be able to fold it over itself without spreading. Add ghee and cook for a minute to bring it together. Don't overcook else the sugar will start to caramelize and barfi will become hard.
Transfer the mixture to a lined tray. Level using a spatula. You can press some nuts on top if you wish.
Cool down completely. Once cooled, I put it in the fridge for 4-6 hours to set.
Once set, you can add some edible gold or silver foil on top. Using a sharp knife cut into as many squares as you wish.