If using unsalted roasted peanuts, just remove the skin and keep it aside.
If using raw peanuts, we need to roast them. We can roast them on stove top, in the oven or in the air fryer.
Roasting peanuts in oven - Preheat the oven to 350 F and place the tray of peanuts in the oven. Bake them for about 15 – 20 mins, rotating the tray twice or thrice in between. Remove the peanuts after about 15 mins and leave it out until it cools down to room temperature.
Roasting the peanuts in air fryer - Preheat the air fryer at 325 F for couple of minutes. Place the raw peanuts in the air fryer basket and roast it for 5 to 7 minutes. Shake the basket well every couple of minutes for even roasting. Once roasted remove it and let it cool to room temperature.
Roasting the peanuts on stove top - This is one of my least favorite way to roast the peanuts. They roast very unevenly when roasted on stove top. If you are roasting on stove top, make sure to keep shaking the pan for even roasting. Roast on low flame so the peanuts don't burn.
Once the peanuts are roasted and cooled down, rub the peanuts in between your palm and remove the skin. We could also place the peanuts between a layer of kitchen towel and rub it well to remove the skin.
Blow the skin away and keep the skinned peanuts in a bowl. If preferred you could also crush the peanuts slightly to break it into halves.
To make the jaggery syrup
Heat jaggery and water and let the jaggery melt. Strain it to remove the impurities and then heat it again. I usually don't strain my jaggery as I hardly find any impurities in this.
We need to allow the jaggery to come to hard ball / candy stage. This is the trickiest part in the recipe. If you have a candy thermometer, go ahead and use it to determine the candy stage of the syrup.
If not keep a shallow plate filled with cold water. Add a drop of syrup to the water and then slowly try to make a ball out of it. If it forms a ball without disintegrating, then the syrup is ready. The ball when dropped on a plate should make a noise.
Pour this syrup on the roasted peanuts or add the peanuts into the syrup and mix it using a wooden spoon. Let it cool slightly.
Grease your palm with little ghee and then start making round balls. Make sure you start rolling it out when the whole thing is still hot otherwise, the peanuts would become hard and it will be unable to roll them.
If the syrup crystallizes before making balls, then slightly heat the tray/plate. This will start dissolving the syrup and then make balls out of the remaining.
Cool the kadalai urundai in a single layer (to prevent sticking with each other) and then store it in an airtight container.