1. In a large deep sauce pan, heat the olive oil over medium heat.
2. Add the onion, carrot and celery, cook stirring occasionally until the onion is translucent, about 10 minutes.
3. Add the pancetta, ground beef and ground pork, turn heat to high and cook, stirring occasionally until meat is browned, about 15 minutes.
4. Add the tomatoes, tomato paste and meat broth, and season with salt and pepper.
5. Let come to a boil, then lower the heat to low and simmer for 2 hours, stirring occasionally.
6. The sauce should be thick with very little liquid left.