Line a fine mesh strainer with several folds of cheesecloth and set it in your sink.
Combine milk, buttermilk and cream in medium heavy saucepan over medium-high heat. Bring to a boil until cooking thermometer registers 185 degrees...if you don't have a thermometer, keep an eye on it to see when the curds (the solid white parts) are mostly separated from the whey (the cloudy liquid). This will take about 10 minutes...stir a couple of times during the boiling process.
Remove from heat and using a slotted spot, scoop spoonfuls of the curd into the cheesecloth-lined strainer, sprinkling with a little salt every few spoonfuls or so.
Let the ricotta drain for about 5 minutes and then taste to check the consistency. If you like it drier, then let it drain a little more. If you like it moister, stir in a tablespoon or two of milk. This ricotta is best used right away, but will keep for a day or two in the fridge.