First thing to do is the ingredient preparation. Take a slice off the “guanciale” and make it into sticks. A 5mm (3/16") thick slice will do; that will allow you to make 5x5mm (3/16"x3/16") sticks, 2cm (3/4") long. Don’t worry if they look a bit chunky; after the frying they will half their size.
Then, remove the plum tomatoes from the can and put them into a container.
Break the plum tomatoes with whatever comes to hand.
Take a frying pan (ideally an iron pan) and pour the extra virgin olive oil into it. Swirl the pan around so that the oil will evenly coat the pan. The fat (olive oil or pork lard) should be minimal, just to allow a thin coating, because after, when we add the guanciale, some of the fat contained in the guanciale will melt, adding extra fat to the pan. Now, heat the oil on medium heat.
When the oil is hot, add the chilli. Do not break the chilli in many pieces; just break it into two, so that it will be easier to remove it from the pan at a later stage.
Add the guanciale into the pan and turn the heat to low.
Quickly stir with a wooden spoon, so that the guanciale sticks are turned as well, to allow an even frying.
After about a couple of minutes, the guanciale sticks should turn to a golden colour. This is the critical stage because frying for longer would dry the guanciale too much, making it too crispy, which is not good for the amatriciana sauce.
So, we stop the frying process, adding the tomatoes to the pan.
Give it a good stir and simmer for about 10-12 minutes, which is the time you need to cook the spaghetti. During this time stir every now and then.
Now, “butta gli spaghetti” (throw the spaghetti in) and boil the spaghetti according to instructions given on the packet. Remember to cook the spaghetti “al dente” and to use 10g (1/3 ounce) salt for each litre (4 1/8 cups) of boiling water.
A few minutes before the end, check the seasoning and add some salt according to your taste.
Also, remove and discard the chilli.
Now, the sauce is ready to top the spaghetti.
When the spaghetti is cooked “al dente”, drain it into a colander and put the spaghetti back into the big pan you have used to cook it.
Add the amatriciana sauce into the pan.
Stir to evenly coat the spaghetti.
Add half of the Pecorino cheese into the pan and stir. Keep the remaining Pecorino cheese for the serving.
Plate the spaghetti, add some extra Pecorino cheese on top and enjoy this fab spaghetti all’amatriciana.