Heat ghee in a heavy bottomed pan. Fry cashewnuts till golden brown. Set aside.
Add the milk, sugar, and semolina to the remaining ghee in the pan. Bring to a boil and cook on low heat, stirring constantly until the mixture becomes very thick. This should take 30 – 45 minutes. Add cardamom powder and mix.
Pour the mithai into a greased rimmed plate. Chop the cashewnuts and sprinkle on top. Score the mithai into squares and cut when cooled. Or if you are in a hurry, scoop out with a spoon and serve immediately.