Pour milk into a large pot. (For extra-creamy ricotta, add the whipping cream, too.) Stir in the salt. Slowly warm the milk over medium heat. When you notice steam and tiny bubbles forming on the surface, check the temperature. At about 180° or 185°, just shy of boiling, remove the pot from the heat.Advertisement
Gently stir in the vinegar. You'll see curds forming immediately. Let stand 10 minutes. Meanwhile, line a sieve with a double layer of damp 100-percent-cotton cheesecloth. Place the sieve in a larger pan. With a slotted spoon, ladle the curds into the sieve.
Let drain for 20 to 60 minutes, depending on how dry you want your ricotta. (A short strain will make a soft cheese for spreading or dolloping. A longer strain yields firm curds to scatter on salads or pasta.) Lift the cheesecloth and squeeze gently. If the liquid runs clear, squeeze a little more. When the liquid runs milky, stop. Discard cheesecloth and drained liquid. You'll have about 4 cups of cheese; store in an airtight container in the fridge for up to 7 days.
Do not use lowfat or fat-free milk to make ricotta. The flavor comes from the fat in the milk.