You’ll be surprised at how easy it is to make ricotta cheese at home: just heat the milk to a boiling point, lower the heat, and stir in vinegar. The curds that begin to form are the ricotta. —Ilona Oppenheim
Bring the milk, half-and-half, and salt to a boil in a heavy pot over medium-high heat. Stir occasionally to prevent scorching. As soon as the mixture starts to boil, reduce the heat to low and add the vinegar. Simmer while stirring very gently until the mixture curdles, 1 to 2 minutes.
Line a large sieve with several layers of fine-mesh cheesecloth and place it over a large bowl. Pour the mixture into the sieve and let it drain at room temperature for 1 hour. Discard the drained liquid or save it for other uses, such as soaking your grains.
Enjoy the ricotta right away while it’s still warm, or refrigerate in an airtight container for up to 4 days.