cabbage soup with farro and onion

Name: cabbage soup with farro and onion
Prep time: 15 min
Cook time: 1 h 20 min
Total time: 1 h 35 min
Cuisine: American
Ingredients: 1/4 cup plus 1 tbsp extra virgin olive oil, divided; 2/3 cup farro; 1 small head of cabbage; 1 medium onion, thinly sliced; kosher salt and freshly ground black pepper; 2 garlic cloves, minced; 1 sprig fresh thyme; 1 tbsp red wine vinegar; 5 cups low-sodium chicken broth, plus more if needed; 1 cup freshly grated Parmigiano Reggiano