Pour the milk into a pot and heat over medium heat to 175 degrees. Stir as necessary to prevent scorching, and turn the heat down it it begins to stick to the bottom of the pan.
Turn off the heat and add buttermilk and lemon juice, stirring to incorporate.
The milk should begin to form curds immediately, but allow it to sit undisturbed for at least 5 minutes. At this point, you should see a clear separation of curds and whey.
Pour the curds and whey into a cheesecloth lined colander. Allow the curds to drain for 2-3 minutes, until they look like a thick oatmeal. (Drain longer for a dryer finished cheese).
Stir in salt and herbs (optional, if using) and serve.