Get a pot of well salted water on to boil so it is ready to cook the pasta when you add the tomatoes to skillet.
I like to blitz the canned tomatoes in a blender or with a stick blender before starting the sauce. It makes a thicker, richer sauce.
Heat a drizzle of olive oil in a large skillet over medium heat and cook the bacon until the fat has rendered and the bacon is golden and crisp, around 8–10 minutes.
Remove with a slotted spoon and set aside, leaving the bacon fat in the pan.
Add the onion and cook for 4-5 minutes until softened and glassy. Add the garlic, red pepper flakes and smoked paprika and cook for another minute.
Add the tomato paste and cook for a minute.
Pour in the tomatoes and return the bacon to the pan and gently simmer for 10 minutes while you cook your pasta.
When your pasta is just about done, add the butter and ¼ cup of pasta water into the sauce and mix in well.
Add the cooked pasta along with the parmesan and toss continuously over low heat until the sauce coats the pasta evenly. Add more pasta water if needed.
Serve with the Italian parsley if using and extra parmesan cheese on top.