Umbrian-Style Lentil Soup | Untried | Umami

Ingredients

• 3 tablespoons extra-virgin olive oil, plus more to serve
• 1 medium yellow onion, chopped
• 2 medium celery stalks, halved lengthwise and chopped
• 2 medium carrots, peeled, halved lengthwise and cut into ¼-inch pieces
• Kosher salt and ground black pepper
• 2 medium garlic cloves, finely grated
• 3 tablespoons tomato paste
• 1¼ cups lentils du Puy, rinsed and drained
• 1 teaspoon dried rosemary
• ¼ to ½ teaspoon red pepper flakes