Steps:

• Cut the pancetta or prosciutto into chunks less than one-half inch thick. Place in a saucepan with the olive oil and fry over low heat for 15 minutes, until all the fat has been rendered out and the meat is very crisp. Remove the meat from the pan with a slotted spoon and set aside.
• Add the onion to the pan and saute over medium heat for five minutes.
• Drain the tomatoes, finely chop them and add to the onion in the pan. Season with red-pepper flakes and salt and pepper to taste and simmer 20 minutes, stirring occasionally.
• Meanwhile, bring a large pot of cold water to a boil and add salt to taste. Add the pasta and cook until al dente, about 9 to 12 minutes, depending on the brand. Drain well.
• Transfer the cooked sauce to a large heavy skillet over medium-high heat. Add the pasta and the reserved meat and cook, stirring, for 30 seconds. Remove the skillet from the heat, add the cheese and mix very well. Transfer the pasta to a warm platter and serve immediately.

Steps:

• Cut the pancetta or prosciutto into chunks less than one-half inch thick. Place in a saucepan with the olive oil and fry over low heat for 15 minutes, until all the fat has been rendered out and the meat is very crisp. Remove the meat from the pan with a slotted spoon and set aside.
• Add the onion to the pan and saute over medium heat for five minutes.
• Drain the tomatoes, finely chop them and add to the onion in the pan. Season with red-pepper flakes and salt and pepper to taste and simmer 20 minutes, stirring occasionally.
• Meanwhile, bring a large pot of cold water to a boil and add salt to taste. Add the pasta and cook until al dente, about 9 to 12 minutes, depending on the brand. Drain well.
• Transfer the cooked sauce to a large heavy skillet over medium-high heat. Add the pasta and the reserved meat and cook, stirring, for 30 seconds. Remove the skillet from the heat, add the cheese and mix very well. Transfer the pasta to a warm platter and serve immediately.