If you have one, you know it's true: Slow cookers are the true MVP of home cooking.

extra-virgin olive oil

boneless pork shoulder

Coarse salt and freshly ground pepper

large onion, finely chopped

garlic cloves, minced

celery stalk, finely chopped

fennel seeds

dry red wine

crushed tomatoes

Cooked polenta

Finely grated Parmigiano-Reggiano, for serving