Heat milk to boiling stage, add any one of - lime juice, citric acid, vinegar, sour whey or sour curd, stirring continuously till the clear whey separates. When the entire paneer is separated from the whey, leave covered for some time .Meanwhile fold thin muslin cloth twice or cheese coth folded twice on a colander, pour the mixture & drain out the whey. Most of the whey will be drained. Now pat roughly into a rectangle, place with cloth on a cutting board, cover with another cutting board over which, a heavy weight should be placed. You can keep a vessel full of water or a clean brick. After a few hours, remove weight, board & muslin cloth – a slab of paneer is ready. If necessary, give a run in the small mixi jar for 2,3 secs( to make it soft & smooth) & shape into a square.
If you use citric acid or lime juice, mix with some water & add for uniform distribution.
For 1 litre of milk,
If using curd, upto 3/4 cup sour curd– 2 tbsp lime juice – ¼ tsp citric acid – upto1/2 cup vinegar will be required.
If using whey, keep adding till the milk curdles completely.
In my personal experience, I find that sour curds give smooth paneer.