My buddy at work has asked me to help him figure out why his Alfredo sauce looks like curds and whey. He has tried making it all sorts of ways...He's varied the liquid (half and half versus whole milk), the temperature (high versus low heat), and the cheese quality (grated parm from Sam's versus other brands of grated parm). No matter what he does it always turns out looking curds and whey. Please help to explain what's gone wrong with his sauce. Also, if you have a tried and true recipe, would you please include it also? Many thanks!!!