Take a heavy bottom pan and add ghee in it and heat on low flame.
Add the sevai/ vermicelli and roast till nice golden in colour. keep stirring while roasting.
When done take out in a bowl and keep aside.
Add 1 tbsp oil in the pan and roast the nuts to a nice golden color and when done take out in a bowl and keep aside.
Soak the saffron in 1 tbsp of milk and keep aside.
Now add the milk in the pan and let it boil over medium heat and keep stirring.
When it come to boil then reduce the heat and let it cook on low heat for 5-6 minutes.
Now add the roasted sevai and stir well to mix.
Now let it cook on low heat approx. for 10 minutes or till sevai become soft and kheer become slight thick .
Now add saffron and sugar and give it a boil , keep stirring so it will not stick or burn at the bottom of the pan.
Cook for 3-4 minutes on low heat so sugar dissolve and cook properly.
You can taste the sugar at this stage and adjust if needed.
Switch off the heat and add the cardamom powder and let it cool down completely.
Peel all the 4 mangoes and make puree of 3 mangoes and chop 1 mango into small pieces
When the kheer cool down completely then add the mango puree in the kheer and add half quantity of roasted nuts in it and keep refrigerated for few hours so it become nicely chilled.
Serve chilled sevai kheer garnished with few mango pieces and sliced nuts.
Enjoy ! stays well in the refrigerator for 2 days