Mix the corn flour in 1 and 1/2 cups of water and whisk well to ensure there are no lumps. Then add the food color and mix well. Keep it aside.
In a non-stick pan add the sugar and 1 cup of water. Boil till the sugar dissolves and the mixture becomes slightly thick and sticky.
Then add the corn flour mixture slowly and keep stirring continuously on a low flame to avoid lumps. It will start looking glossy here and there and then start to thicken. Keep stirring till you see the halwa texture.
Add ghee and cardmom powder. Once it starts leaving the sides and comes as a whole mass, add the cashew nuts, mix well and turn off the flame.
Pour this in a greased pan and allow it to cool. Once cooled, slice it into desired shapes and serve.
Garnish with grated cashews and serve.