Heat a large pot of heavily salted water to a boil and cook the pasta according to package directions.
Heat a large saute pan to medium heat and add the pancetta. When it has rendered out most of the fat, add the carrot, celery, onion, and garlic. Saute for 2-3 minutes.
Add the ground lamb and break it up into pieces. brown.
Add tomatoes, Italian seasoning, and balsamic vinegar.
Cook for 20 minutes.
Add the cooked rigatoni to the saute pan and mix well. Top with ricotta cheese and broil until the cheese is melty and golden,