Squeeze the juice of a good sized lemon into a bowl. We had 2 small lemons that I thought were close to equaling a large one. No pits please. Then a spoonful of mustard. I am not giving exact measurements as I want you to see how easy this is and you can make it more lemon-y or mustard-y by adding more or less. Then add a few good pinches of salt & pepper. Eyeball and add twice as much extra virgin olive oil as what is in the bowl. A 2 to 1 ratio of oil to acid is great here. Now with a fork, whisk it all together. The mustard will magically make it all mix together making a pretty darn yummy dressing. Now add the freshly grated Parm to the mixture. It adds a textured creaminess that takes it all to a different level. It becomes a thicker, richer vinaigrette, perfect served as is over your desired greens. Enjoy!