Bring a large pot of well salted water to a boil over high heat. Add your pasta and cook to 1 minute before the package time. Sprinkle a little salt on your chicken livers at the same time. (Note the photo here is pre-chopped, your liver should be more chopped than this).
While the pasta is cooking, heat up your oil in a large non stick skillet over medium heat. If you are going to fry sage leaves, drop them carefully in the oil for 30 seconds per side, then remove to a paper towel to drain.
Cook the shallot and guanciale until the shallots are translucent, about 2 minutes. Add the garlic and chopped sage. Cook until the garlic is fragrant, stirring frequently so the garlic doesn’t burn, 1-2 minutes.
Add the tomato paste and continue to stir. Cook until the tomato paste has darkened slightly, 1-2 minutes.
Add the liver and wine, turning the heat up to medium-high. Crush the liver into tiny bits if needed. Once the wine has reduced by half (about 2 minutes), add most of the cheese, toss to mix lightly, then reduce the heat to low while you wait for the pasta to finish. Taste and season the sauce with salt and pepper.
Once the pasta has finished cooking, transfer it to the skillet using soft tongs or a spider. Alternately, reserve 1/2 cup of pasta water and drain the pasta, then transfer to skillet without rinsing. Turn the heat up on the skillet to medium high and toss until well coated. If the sauce seems dry, add pasta water, 1/4 cup at a time, as needed.
Top with remaining cheese, black pepper, and sage leaves, if using.