In a large skillet, over medium heat, add the onion to the olive oil and sauté until golden. Add the prosciutto and stir together until fully incorporated and slightly browned – be careful not to let it get crispy. Add the tomatoes and salt and pepper. Cook for 10-15 minutes until the sauce has slightly thickened.
Bring a large pot of salted water to a boil.
Cook the pasta until al dente (about 2 minutes less than the package directions). Drain, and add to the prosciutto mixture.