THE METHOD: 

1. Heat the Milk: In a large pot, heat the milk over medium heat until it reaches a gentle simmer, stirring occasionally to prevent scorching.
2. Add the Acid: Once the milk is simmering, add the lemon juice or vinegar and stir gently to combine. Continue to simmer for a few more minutes until the curds start to separate from the whey.
3. Strain the Curds: Line a colander with cheesecloth or a clean kitchen towel and place it over a large bowl. Carefully pour the curds and whey into the colander, allowing the whey to drain away and leaving behind the ricotta curds.
4. Season and Serve: Once the ricotta has drained to your desired consistency, transfer it to a bowl and season with salt to taste. Use immediately or store in an airtight container in the refrigerator for up to one week.