In a large skillet, combine ricotta, condensed milk, sugar & milk powder. Mix well. Turn heat to medium.
Simmer while stirring regularly. Cook for 10-12 minutes, until the ricotta mix reduces down to half.
When it reduces to a fudge-like consistency, stir in ghee & cardamom powder. Cook for 2 mins.
Kalakand is ready when it stops sticking to the pan. Turn off the heat and place the pan on a cool surface.
Pour the Kalakand mix in a parchment-lined pan and spread it into an even layer. Top it with chopped nuts.
Chill in the refrigerator for 4 hours, then cut into squares. Kalakand is best served slightly chilled.