Heat 2 tablespoons of ghee in a heavy-bottomed pan or kadhai over medium heat. Add the grated carrots and sauté for 5 minutes until they soften slightly and release moisture.
Pour in the milk and stir well. Bring to a gentle boil, then reduce the heat to medium-low. Let the carrots cook in the milk, stirring occasionally to prevent sticking at the bottom.
Continue cooking for 30 to 35 minutes until the milk reduces by three-fourths and the carrots absorb most of the liquid. The mixture should look thick and moist, not soupy.
Add the sugar and crushed cardamom. Stir well and cook for another 5 to 7 minutes until the sugar dissolves completely and the halwa thickens further. The mixture will start leaving the sides of the pan.
In a small pan, heat the remaining 2 tablespoons of ghee. Fry the cashews, almonds, and raisins until the cashews turn light golden. Pour this tempering over the halwa and mix well.
If using saffron, soak the strands in 1 tablespoon of warm milk for 2 minutes, then add to the halwa. Stir and cook for another minute.
Turn off the heat. Let the carrot halwa rest for 5 minutes before serving. It will thicken slightly as it cools.
Notes
Pan choice – Use a heavy-bottomed pan or non-stick kadhai to prevent scorching. A wide pan helps milk evaporate faster.
Make-ahead – You can make this halwa 2 days in advance. Store covered in the fridge and reheat gently on the stove with a splash of milk.
Freezing – Carrot halwa freezes well for up to 1 month. Thaw in the fridge overnight and reheat before serving.
Carrot quality – Choose firm, naturally sweet carrots. Avoid old or woody carrots as they take longer to soften and taste bland.
Consistency control – If the halwa looks too dry, add 2 to 3 tablespoons of warm milk and stir. If too runny, cook on low heat for a few more minutes.
Serving temperature – Carrot halwa tastes great warm, at room temperature, or chilled. Try all three and pick your favourite.
Garnish ideas – Top with extra nuts, a drizzle of warm ghee, or edible silver leaf for special occasions.