Add a splash of water to the skillet and fry bacon for 2-3 minutes until lightly browned (no oil is needed as bacon provides plenty of fat). Add the onion and stir for another minute or two until softened.
Meanwhile, cook the penne according to package instructions, in a pot of salted water.
Pour the wine into the bacon mixture and allow to bubble down, then stir in the passata and oregano. Bring to a simmer, then stir in creme fraiche. Season to taste. Cover and simmer for 5 minutes until slightly reduced and thickened. Stir in the peas and cook for another 3-4 minutes.
When the pasta is cooked, drain and rinse in hot water, shaking the pasta to get water out of the tubes. Fold in the bacon and pea mixture, and season to taste.