Put the whole milk in a large saucepan and bring it to the boil. Just as it starts to come to the boil, stir in three tablespoons of the lemon juice or the white wine vinegar, whichever you are using, and remove from the heat. The milk should start to curdle immediately. If it doesn't, bring it to the boil again and stir another tablespoon of lemon juice or vinegar, whichever you're using, then turn off the heat as before. Allow to stand for about 10 minutes, when the curds should be completely separated, and the liquid should be yellow and watery.
Place a large sieve over a deep bowl. Line the sieve with a double thickness of muslin or cheesecloth, then pour the curds and whey into the lined sieve, allowing the whey to drain away in to the bowl. It will take about 45 minutes for the whey to fully drain.
Gather up the ends of the muslin and gently squeeze it to remove the excess whey.
Open the muslin again and sprinkle ¼ teaspoon of salt over the curds. Taste and add more salt if you like.
Transfer the curds, which are still in the muslin, to a large dinner plate. Shape them in to a rough square, then fold in the muslin tightly around the curds to form a neat, square package. Place a second plate on top of the package to weigh it down. Leave the paneer like this for at least 15 minutes and up to an hour, if possible.
The paneer is now ready to use. You can use it immediately, or keep it in the fridge for up to two days. Cut the paneer into cubes of about 2cm (1in) when you're ready to use it.