Line a large sieve or colander with a double layer of fine-mesh cheesecloth and place it over a large bowl.

Slowly bring the milks, cream and salt to a low boil in a large (4 qt or more) heavy pot over medium heat, stirring occasionally but shallowly, to prevent scorching (try not to scrape the bottom of the pot while stirring once the heat gets going. Scorching happens, and you don't want brown bits floating around in your ricotta). When the mixture reaches 190°F, remove from the heat and add the lemon juice. Stir gently until the mixture curdles (i.e., when the curds separate from the liquids in big, floating icebergs), about 2 minutes.

Spoon the solid curds into the lined sieve and let drain for an hour (or an hour and a half for a drier curd). Move the ricotta to a bowl and give it a good stir. If the curds are too crumbly (i.e., too dry), add a bit of the drained liquid, stirring well to incorporate until you reach the desired consistency. Add the herbs and work them in with a spoon to combine. Cover and chill in the fridge. Discard the liquids or use for another purpose, such as bread-making (the liquid by-product of this process is whey, and whey is a wonderful substitute for the liquids in a yeast bread recipe). The ricotta will keep in the refrigerator for 2 to 3 days.