- Toss the bread cubes in the milk and let sit for 10 minutes.
- In a large skillet, heat half the oil.
- Add the onion.
- Cook over medium-low heat until onion is soft and translucent, about 3 minutes.
- Add spinach and cook until soft and tender, about 7 minutes more.
- Season to taste.
- Place the spinach in a sieve to drain.
- Meanwhile, squeeze out excess milk from the bread, little by little, and discard milk.
- When spinach has cooled, press it into sieve (or between your hands) and try to extract as much juice as possible.
- In a food processor, puree the spinach.
- Add the bread, egg and feta cheese and process until it comes together like dough.
- Place in a bowl. Salt and pepper to taste.
- With floured hands, shape into small round, marble-sized dumplings.
- Crush the coils of angel hair pasta with your hands into ½-inch-long pieces.
- In a large soup pot, warm the remaining ¼ cup olive oil.
- Add the broken pasta and stir to coat with a wooden spoon.
- Saute for 5 minutes, stirring constantly, until pasta is golden brown.
- Add broth and simmer until pasta is cooked.
- In a separate bowl, combine the yogurt, egg yolks, flour, dried mint and cayenne, and whisk until smooth.
- Ladle a cup of the hot soup into the yogurt mixture, whisking until combined.
- Add yogurt mixture to the soup pot, whisking for about 5 minutes until the soup starts to simmer.
- Add dumplings and continue to gently simmer another 10 minutes.
- Be careful not to boil.
- Ladle into bowls.
- Drizzle with olive oil and sprinkle with sumac.