"In the case of mascarpone, you heat some heavy cream until it’s just about to boil and then add some acidity in the form of a tablespoon of lemon juice. To make ricotta, you heat milk and buttermilk (which can easily be made at home with whole milk and lemon juice) until it’s just about to boil. Drain the resulting products and you either mascarpone or ricotta, depending on what you started with."
http://londonbakes.com/2012/09/homemade-mascarpone.html
That's it?
