Roast the rice flour in a pan on low flame until the colour changes from white to light brown or orange. Keep it aside.
Soak the cowpeas (karamani) overnight and pressure cook them until soft.
In a heavy-bottomed vessel, add 1 cup of water and jaggery. You can use the water used for cooking the cowpeas. Allow the jaggery to dissolve completely.
Add cardamom powder and the cooked cowpeas to the jaggery mixture and bring it to a boil.
Once the mixture starts boiling, add the roasted rice flour and mix well to avoid lumps.
Add ghee and mix again. Turn off the flame and keep the dough aside.
After about 10 minutes, apply a little ghee to your hands and knead the dough well until it becomes soft.
Place a small ball of dough on a polythene sheet and press it into a round shape. Make a small hole in the centre.
Remove the shaped adai from the sheet and place it on the idli plate.
Fill all four idli plates and steam cook them. You can place about 8 adais on each plate, allowing you to cook up to 40 adais at a time. Steam for 15 minutes.
Open the cooker lid, gently remove the adai from the idli plates, and transfer them to a hot pack.