Line a large colander with a layer of cheesecloth and place in the sink or over a bowl if you want to save the whey. Wet the cheesecloth to hold it firmly in place.
Over medium-high heat, bring the milk/creams and salt to a gentle simmer in a heavy large pot. Stir in the lemon juice and continue to simmer gently until curds begin to form and float to the top, 1 to 2 minutes. They will first look like spatters of white, then gather into soft, cloud-like clumps.
When you see the liquid begin to clear of cloudiness and the curds are firming up but not hard, scoop them out with a slotted spoon or sieve. My liquid didn't really clear and my curds didn't really firm up so I just poured all of the liquid into the cheese cloth lined colander and a sieve. This seemed to work just as well, but it required draining over night. I let the sieve sit out covered with a cloth napkin and I gathered the ends of the cheese cloth and suspended it on the kitchen sink faucet to drain. My house is kept pretty cool at 55-60 degrees though so I had no problem leaving it out- if your house is pretty warm, I'd suggest suspending them in a cooler place if leaving overnight.
Let the curds drain thoroughly in the lined colander. If very soft, press gently to extract a little moisture, but take care not to dry out the cheese. Turn into a bowl, cover and chill. Store in fridge up to a week.