Peel and grate the carrots. Add the grated carrots and milk to a pressure cooker. Cook for 1 whistle. Take the cooker off the heat and release the pressure immediately by placing the cooker under running water.
Take a tablespoon of ghee and fry the cashewnuts and raisins. Set aside.
Take the lid off the cooker. Add the sugar and cook the carrot mixture on high flame, stirring frequently, till excess liquid evaporates and the mixture is almost dry. This should take 15 – 20 minutes. Add the khoa, ghee, and cardamom powder. Stir and cook 10 minutes longer, till the ghee starts separating from the halwa. Garnish the halwa with the nuts and raisins and serve hot or at room temperature.
I like to serve the halwa hot with some cold vanilla ice cream on the side.