SpaghettiOs and Sausage Soup

Bahan-bahan (6 porsi)

• 1 tablespoon olive oil
• 1 pound ground Italian sausage (mild or spicy)
• 2 tablespoons butter
• 1 medium onion, finely chopped
• 4 cloves garlic, minced
• 3 tablespoons tomato paste
• 3/4 teaspoon crushed red pepper flakes (more or less to taste)
• 1 1/2 teaspoons dried oregano
• 1 1/2 teaspoons fine sea salt (plus more to taste)
• 7 –8 cups chicken or vegetable broth
• 1 Parmesan rind
• 8 ounces anelli siciliani (or other small pasta)
• 3 –4 cups chopped kale, ribs removed
• fresh lemon juice (optional)
• freshly-grated Parmesan, for serving