Slow Cooker Mushroom Barley Risotto

INGREDIENTS

• 3 cups lower-sodium vegetable broth
• 1 ounce Parmesan, grated (2/3 cup)
• Kosher salt and freshly ground black pepper
• 1 tablespoon sherry vinegar
• 1 large onion, finely chopped
• 2 tablespoons extra-virgin olive oil
• 1 pound cremini mushrooms, sliced
• 8 ounces carrots, finely chopped
• 1/4 cup chopped fresh flat-leaf parsley
• 4 sprigs fresh thyme
• 1 1/2 cups pearl barley