There are lots of sweet dishes prepared under this name. Payasam in TamilNadu meals is somewhat similar to the 'kheer' in North India.
Basically, you add sugar or jaggery to well-cooked rice or dal or any pasta, (usually cooked in milk or coconut milk for added rich taste). Let it blend into the payasam on slow heat. Then garnish it with pieces of nuts and dry fruits fried in ghee.
So the recipe is limited only to your imagination. All the recipes that appear here are what I have evolved from my mother's recipes and improved over time with tips from various people.
You can make Semiya payasam in a jiffy. Here is the recipe:
Semiya (vermicili- Thin sticks of pasta) 1/2 cup, broken into small pieces (or you can use the ready made Bambino broken semiya)
Sugar 1 cup
Milk 1 litre
cardamom powder 1/2 tsp
Ghee to roast the semiya
Cashewnuts and raisins (broken and roasted )
Mix 1 tsp of ghee with the semiya in a microwave vessel. Cook on high for 1 minute to roast it slightly.
Mix half the hot milk with it and cook further for 6 minutes or till the semiya is tender.
Add the sugar and cook till it is dissolved.
Add the rest of the milk and cook till it is thick.
Flavour with cardamom powder
Garnish with roasted cashewnuts and raisins.
Alternatively you can add milkmaid at the end instead of boiling the milk. Adjust the amount of sugar for this.
For semiya you could substitute sabudhana. You can cook rice or puffed rice (poha) also instead of semiya. You can use channa dal or moong dal too. In case you use dals, add jaggery instead of sugar, and coocnut milk instead of ordinary milk, to make it more delicious and differntly flavoured.