Fill a pot with 4 qt of water and bring it to a boil.
Then, pour 1 tsp of olive oil into a skillet, slice the guanciale into strips and add it to the pan. Cook at low heat until the guanciale is crispy
Discard the fat from the guanciale and add 250g of crushed San Marzano tomato. Cook for 15 minutes at low heat until the sauce is thick enough to cover the back of a spoon.
Next, add 30 g of nduja and let it melt into the sauce.
When the water is boiling, add 1 tbsp of kosher salt and 120gr of spaghetti.
After 3 minutes, drain the spaghetti a throw it into the pan with the sauce. Finish by cooking the pasta into the sauce, adding starchy water and stirring constantly. When your pasta is ready, turn off the stove add 1 tbsp of starcciatella cheese.
Plate immediately and add one more tbsp of stracciatella on top. Buon appetito!