In a wide bowl, take maida, cooking soda and a pinch of salt. Add melted butter and make a crumbly mixture. Fat should be well distributed with the flour.
Add enough water to make a soft, non-sticky pliable dough. Knead the dough well for five minutes. Keep covered for 30 minutes.
In the mean time, make the stuffing. Take the sugarless khova in a bowl in room temperature. Mix well to break the lumps and set aside. Dry roast the nuts in high flame for 2 minutes. Color of the nuts should not change. Powder the roasted nuts along with sugar. Mix this powder and khova to make a thick stuffing. Set aside.
After 30 minutes, make small lemon sized balls out of the dough. Roll the dough into a small poori of palm size. Make it thick in the center and thin in the corners. Keep 2 tsp of stuffing in the center and fold it like a half moon.
Seal the edges by dipping your finger with water. Once it is sealed completely, do the spirals. While making the spiral shape, if your fingers are sticking to the dough, dip your finger in maida and proceed. You may get some excess dough. Pinch the excess dough and set aside. Fold the corner. Please refer the below picture for reference. This is chandrakala/Half moon shaped sweet.
For suryakala, divide the lemon sized ball into two and roll it to two small pooris. Place the stuffing in one poori and cover it with another poori. Seal the edges with water as mentioned above. Twist the corners and make spirals.
Arrange the prepared suryakala and chandrakala in a plate. Cover it with a wet cloth till you deep fry. Heat oil in a kadai for deep frying. Deep fry them in batches till they turn golden brown on both sides. Drain in a tissue.
Now prepare sugar syrup. Melt sugar in water and boil till frothy. Check for one string consistency. When you take the syrup and slide between your thumb and pointer finger, when you release it, it will form a single string. Dip suryakala and chandrakala into the sugar syrup for 10 minutes till the next batch is ready. It will get a nice shine. After sometime sugar will be coated on top of it.