In a frying skillet over medium heat, cook the onions and the bacon with the olive oil until the onions are translucent. Add the wine. Lower the heat and let it cook for a couple of minutes.
Meanwhile, in a large pan, boil the water with salt. Cook the fettuccine pasta al dente - 8 minutes.
Reserve 1 cup of the cooking water and drain the fettuccine.
In a large serving bowl beat the eggs and Parmigiano Reggiano until all is well incorporated.
When the pasta is done, Immediately add it to the egg mixture and mix well until all the pasta is coated. Add the bacon-onion - wine mixture and stir until all blended. If it is too dry, add some of the cooking water.
Giangi's Kitchen provides nutritional information, but these figures should be considered estimates, as a registered dietician does not calculate them.