Melt ghee in a pan on medium heat. Once the ghee melts, add atta to it and mix to combine well with the ghee.
Meanwhile heat 1 cup water in a pan on another stove. You want to the water to be boiling hot when you add it to the ghee-atta mix. So keep it ready to go.
Continue to stir the atta and cook until it turns brown in color and gives a nice aroma, take around 6 to 7 minutes on medium heat.Be careful to not burn the atta here.
Add the hot water now. Be careful as you add it since the halwa will bubble like crazy.
Stir continuously for a minute or two as you add the water and the water gets absorbed by the flour.
Add in the sugar and mix. The halwa consistency will become liquid-y again after adding sugar. Continue to cook for 2-3 more minutes on medium heat after adding the sugar.
Add cardamom powder and mix (optional). Stir to mix in the cardamom powder and remove pan from heat.
Serve atta halwa immediately. It tastes best when warm! You may garnish with some nuts.
Notes
If you want, you can add nuts like cashews and almonds to the halwa. Either roast them separately or you can roast it along with the atta.
Some people also like to adding some sooji (semolina) to the atta halwa for texture. You can add 1 tablespoon of it here and roast it along with the atta.