• cut the bacon in pieces
• in a large pot add boiling water for the pasta
• cook the pasta
• add the bacon in a cold pan
• heat up to medium low temperature, we don't want to fry it but to melt the fat slowly

Sauce

• in a bowl add the 4 egg yolks and whisk them together
• add the grated pecorino and parmesan cheese, mix it in slowly
• add a spoon of the pasta water in the bowl with the egg mixture to make it thinner and mix that up
• add the cooked pasta in the pan with the bacon
• add the egg mixture in the pan and mix it well until it forms a nice thick sauce on the pasta
• ready to serve