1) Add the diced guanciale (or bacon) to a dry non-stick pan and put it over medium heat. Season with a little pepper. Cook the guanciale for about 5 to 6 minutes until crisp and cooked through. Stir regularly.

2) Put a large pan of salted water to a rolling boil and add the spaghetti until tender.

3) In a metal bowl whisk together the eggs yolk, pecorino and parmesan cheese. Season with some pepper. Place it over a pan of gently boiling water and keep whisking the eggs. This bain marie water bath has to warm the eggs through, but make sure you don't end up with scrambled eggs.

4) Add the cooked guanciale and the grease from the pan to the eggs. Stir well.

5) Drain the cooked spaghetti and transfer it to the bowl with eggs. Take the bowl off the pan of water and stir very well to coat the pasta entirely with the egg sauce.

6) Check the seasoning and add extra pepper to taste.

7) Transfer the spaghetti carbonara onto plates and sprinkle with extra pepper and grated cheese. Serve piping hot.