Bring a pot of very salted water to a boil. Add Pasta (1 pound) and cook until al dente, but do not drain.
In a bowl mix yolks of the Egg (4), Ground Black Pepper (1/4 teaspoon), and half the Pecorino Romano Cheese (2 cup).
In a frying pan, cook the Guanciale (0.25 pound) until browned.
Turn heat to low and add in al dente pasta directly from the pasta water to the bacon (tongs are helpful here). Stir to help the water from the pasta deglaze the pan.
Add in egg and cheese mixture and a little pasta water, stir to combine, then turn off the heat. The sauce should not be mixed with too much heat on or the eggs will cook and make your sauce lumpy.
Add in some of the pasta water as needed to thin out the sauce and fully combine. I like to add the water to the egg bowl first to get the remainder out. Add in remaining Pecorino Romano Cheese (2 cup) and stir to combine.
Plate the pasta while hot. Garnish with some additional guanciale and pecorino if desired and serve.