Heat up a pan, add 3/4 cup of ghee, when the ghee is slightly hot, add a cup of rajgira flour, mix it well with ghee. Fry on medium heat, constantly stirring with a spatula until it turns golden brown in color. Do not let it burnt.
When the flour is looking nice golden and release aroma that time add 1 ½ cup of hot milk, and stir continuously and carefully, until milk get fully absorb by the flour, keep the flame law.
When the milk is absorb well, add 1/2 cup of sugar (sugar you can use according to your taste), mix it well, stirring constantly till it gets thick and all the moisture is evaporated. Ghee come out from the sides. Halwa will leave the sides of the pan.
Add chopped nuts and cardamom powder, Mix everything well.
Cover the lid and cook for another 2-3 minutes on medium flame. After 2-3 minutes remove the lid, Rajgira halwa is ready. Serve hot.