Wash, peel, and grate 4 cups of carrots
Heat 2 tablespoons ghee in a heavy pan
Add the grated carrots and sauté for 5 to 7 minutes
Pour in 4 cups full-fat milk
Cook on medium heat, stirring often, until the milk reduces completely
Add 1/2 to 3/4 cup sugar
Mix well and cook until the halwa thickens
Add 1/4 teaspoon cardamom powder
Add 2 to 3 tablespoons chopped nuts
Add 1 to 2 tablespoons raisins if desired
Cook for a few more minutes until glossy and well combined
Turn off the heat
Garnish with more nuts if desired
Serve warm