Sweet Potato Soup with Feta and Za'atar Oil

Ingredients

• 1/4 cup plus 2 tablespoons olive oil
  
• 2 tablespoons za'atar (see headnote)
  
• 1 tablespoon butter
  
• 1 onion, peeled and diced
  
• 1 carrot, peeled and diced
  
• 1 leek, white part only, rinsed thoroughly and diced
  
• 5 medium sweet potatoes, peeled and cut into 1" cubes
  
• 6 cups water
  
• 2 cups chicken stock
  
• 1 bay leaf
  
• 1 tablespoon salt
  
• 1/4 cup feta cheese
  

Directions

1. In a small pot, combine ¼ cup olive oil and the zaatar. Cook over medium heat until hot, but take care not to burn the zaatar. Set aside for at least one hour to cool and infuse.
2. In a large pot, heat the butter and remaining olive oil over medium high heat. When the butter has melted, add the onion, carrot, and leek, and cook until softened, about five minutes. Add the sweet potato cubes and sauté for another minute. Add the water, stock, and bay leaf, and bring to a boil. Once the soup begins to boil, lower to a simmer and cook for 30 minutes. Check to make sure the sweet potatoes are completely soft. If not, continue cooking until they are.
3. Remove the bay leaf and puree the soup using a regular or immersion blender. Check the seasoning and add the salt (you may need more or less depending on what type of stock you used). Ladle out the soup into individual bowls. Crumble some feta into each bowl, and drizzle each bowl with some of the zaatar oil.