Chop the nuts and dry roast on a low heat until crunchy. Set aside to cool.
Bring milk to a boil in heavy bottomed pan, add grated carrots and begin to stir. Cook until the milk has completely evaporated.
Add sugar and stir. Sugar would release lot of moisture. Cook until half the moisture evaporates. Add clarified butter and stir well.
Continue to cook until the moisture evaporates and the halwa thickens. At this point add grated khoya, stir and cook for 2 minutes.
Garnish with nuts and serve warm or chilled.