You need a big, heavy bottomed pot so that your milk won't scorch, and a thermometer (I used a candy thermometer). Pour in 2 quarts of whole milk and 1 cup of heavy whipping cream.
Heat over medium heat, stirring so that it doesn't scorch, until it reaches 185 degrees F (85C) It doesn't usually take very long.
Turn off the heat and add 3 Tablespoons (44 ml) of either vinegar or lemon juice. White vinegar is probably best, but I'm out, so I used cider vinegar. This is your curdling agent.
As you stir, the curds should start forming.
After stirring for a minute or two, cover the pot with a clean cloth and go watch a few episodes of Flower Boys Next Door. Let it sit for about 2 hours.
Ok, now you're ready to pour off the whey. Place a strainer in a bowl.
Line the strainer with cheese cloth.
Use a slotted spoon to scoop out the curd and put it into the cheesecloth-lined strainer. I usually scoop as much as I can into the strainer, then carefully, slowly pour all of the liquid through the strainer. You can only do this if your bowl is big enough to catch all the whey BELOW the strainer. This a really big stainless mixing bowl.
Stir it carefully...you don't want to press the curds into the cheesecloth too much, but it will help the whey to drain through.
Let it drain for 2-3 hours. Time for a couple more episodes! In between eps, or during commercials, pull up the four corners of the cheesecloth and gently squeeze the whey out.
There you have it, fresh ricotta. This is ready for putting in your favorite lasagna, baked pasta, stuffed shell recipe. It's great with ANY recipe that calls for ricotta, including desserts. It will keep for 3-4 days in the refrigerator. If you are counting calories, this is a higher fat content than the part-skim ricotta that you find in the grocery store. I've seen recipes for that, but you get so little curd from it that it's not worth the trouble.
Update May 2015: After a couple of batches that didnt curdle right, I did some research and found that you can use up to 1/3 cup of your curdling agent. I didn't want to start over, so I heated it back up, added 2-3 tablespoons more lemon juice (or vinegar) and it worked. Didn't seem to affect the taste or consistency.
Don't throw away the whey! You can use it in any baked good recipe that you use milk in....pancakes, etc. It has protein and you've just taken most of the fat out of it!
You can use the cheesecloth several times, just rinse it out really well and then I run it through the washer on hot without soap.