1/2 cup extra virgin olive oil, plus extra for drizzling
1/2 medium red onion, diced
1 carrot, diced
1 rib celery, diced
4 pork spare ribs
1 cup crushed plum tomatoes (peeled and seeded)
2 8-oz cans cranberry or red kidney beans, drained and rinsed
4 cups beef broth (low sodium)
kosher or sea salt and freshly ground black pepper
1/2 pound tubettini or small shells pasta
1 tablespoon unsalted butter
2 tablespoons grated Parmigiano Reggiano cheese, plus extra for garnish
Garnish