Spring Veggie Soup With Ditalini

Name: Spring Veggie Soup With Ditalini
Ingredients: 4 celery ribs (cut into 1-inch pieces); 4 carrots (cut into 1-inch pieces); 2 yellow onions (halved); 1 leek (cut into 1-inch pieces); 1 fennel bulb (halved, cored and cut into 1-inch dice); 3 parsley sprigs; 2 thyme sprigs; Kosher salt; 1 cup pasta (ditalini, dry); 1 teaspoon olive oil (extra virgin olive oil, plus more for drizzling); 1/2 pound asparagus spears (tough ends trimmed, stalks thinly sliced on the diagonal); 1 cup green peas (fresh or frozen baby peas); 1 cup fava beans (shelled, fresh or frozen shelled edamame, thawed); 1 cup flat-leaf parsley leaves