Pour the milk, cream and salt into a large non-reactive pot. Attach a candy or deep-fry thermometer and over medium heat, heat the milk to 190 °F (88 °C). Stir every now and then to prevent scorching on the bottom of the pot.
7 cups (1656 ml) whole milk, 1 cup (240 ml) whipping cream, 1 teaspoon coarse sea salt
Remove the pot from the heat and then add the lemon juice. Slowly stir the mixture once or twice. Go away so you’re not tempted to mess with it and come back 10 minutes later.
6 tablespoons freshly squeezed lemon juice
Place a colander over a large bowl, making sure that there’s an inch or two between the bottom of the colander and the pot. Line the colander with a few layers of cheesecloth. Pour the ricotta mixture over the cheesecloth lined colander.
Strain it at least for two hours. It will firm as it chills so don’t be worried that it’s not firm yet.
Shelf life varies depending on the milk you used, but it should stay good for at least 3-4 days. Just give it a smell and you’ll know if it’s good or not.