Remove the milk from heat. Pour in the lemon juice or vinegar and the salt. Stir gently to combine.

Let the pot of milk sit undisturbed for 10 minutes. After this time, the milk should have separated into clumps of milky white curds and thin, watery, yellow-colored whey — dip your slotted spoon into the mix to check. If you still see a lot of un-separated milk, add another tablespoon of lemon juice or vinegar and wait a few more minutes.

Set a strainer over a bowl and line the strainer with cheese cloth. Scoop the big curds out of the pot with a slotted spoon and transfer them to the strainer. Pour the remaining curds and the whey through the strainer.

Let the ricotta drain for 10 to 60 minutes, depending on how wet or dry you prefer your ricotta. Refrigerate what you don’t use.