Soak saffron threads in 2 tablespoons of hot water and keep it aside.
Heat 2 tbsp of ghee in a pan or kadhai on medium heat. Add cashews and roast on low flame until light golden brown. Strain and transfer them to a plate.
Add raisins and fry them on a low flame until they swell up and double their size. Strain and transfer them to a plate. Set aside.
Add ¼ cup of ghee to the same pan and melt it completely. Add rava or semolina and roast it on a medium flame. Roast the rava for 8-10 minutes or until it becomes fragrant and changes its colour to light pink.
Add 2 and ½ cups of water to the roasted rava. Mix it well and break all the lumps.
Cover the pan with a lid and turn the flame to flame. Let the rava absorb the water completely; it will take around 3-4 minutes.
Open the lid and stir the rava. Add sugar and stir it continuously until the sugar dissolves completely.
Once the sugar dissolves completely, add 2 tbsp saffron water, cardamom powder and Kesari or orange food colour (optional). Mix it well and stir continuously until the halwa absorbs the saffron water and food colour.
Now, add roasted cashews and raisins. Stir well and ensure the mixture is combined well and there are no lumps.
Add 2 tablespoons of ghee and mix well until the rava kesari separates from the sides of the pan or kadhai.
Rava kesari or kesari bath is ready to serve. Serve it warm and garnish it with roasted cashews.