Pasta and Lentil Soup

Name: Pasta and Lentil Soup
Ingredients: 5 tablespoons extra-virgin olive oil, plus more for drizzling; 1/2 onion, chopped; 4 cloves garlic, smashed; 1/4 to 1/2 teaspoon red pepper flakes; 2 tablespoons tomato paste; 2 cups low-sodium chicken broth; 1/2 cup grated parmesan cheese, plus 1 piece cheese rind (optional); 8 ounces orecchiette or other small pasta; 2 14-ounce cans lentils (1 undrained; 1 drained and rinsed); 1/3 cup roughly chopped fresh parsley; Kosher salt; Crusty bread, for serving (optional)