best lentil soup

Ingredients

• 2 tablespoons extra-virgin olive oil
• 1 medium onion, chopped
• 4 medium carrots, chopped (2 cups)
• 2 celery stalks, chopped
• 6 small or 3 large kale leaves, stems finely diced, leaves chopped (8 cups)
• Heaping ½ teaspoon ground cumin
• 1½ teaspoons sea salt
• Freshly ground black pepper
• 4 garlic cloves, grated
• 1 (14-ounce) can fire-roasted diced tomatoes
• ¾ cup dry green lentils, rinsed
• 2 tablespoons white wine vinegar
• 12 fresh thyme sprigs, bundled
• 6 cups vegetable broth
• ½ cup chopped fresh parsley, for garnish
• Red pepper flakes
• Grated Parmesan cheese, for serving, optional