In a large soup pot over medium-high heat, add the butter or olive oil, onion, garlic, miso, if using, and salt and cook until softened, adjusting the heat as needed and stirring occasionally, 5 to 10 minutes.
Step 2
Add the cooking liquid, vegetables and herbs and bring to a simmer. Cook, uncovered, adjusting the heat as necessary to maintain a simmer and stirring occasionally, 15 to 20 minutes. (Cooking time will vary depending on vegetable selection and whether they are cooked or raw.)
Step 3
Add the cooked starch, and simmer, uncovered, for 5 minutes. Taste, and season with more salt as needed.
Step 4
Ladle the soup into bowls and drizzle generously with olive or herb oil. Top with the tapenade and parsley leaves, if using, and serve.
