Creamy Leek Soup

Why I Love This Recipe
Isn't it lovely to treat oneself with something warm and smooth on a cold day, that is light and tastes great as well? I enjoyed this soup a lot.
Ingredients You'll Need
2 leeks
4 shallots
1 potato
1 celery stalk
1 liter (4 C) vegetable stock(homemade or buillon)
2-4 TBspoons Greek yogurt
4 slices pancetta or prosciutto
1 bay leaf
Directions
Clean, wash and slice the leeks (I used not only the white part but the more tender internal green leaves as well).
Clean and chop finely the shallots, the cellery and the potato.
Sautè all the vegetables with 2 TBspoons of EVOO for a couple minutes.
Add the hot vegetable stock and the bay leaf, cover, lower the heat and cook for 25 minutes. Since I used buillon, I didn't add any salt later, so adding more salt is up to you.
Remove the bay leaf and pureè everythng in a blender.
Distribute into four soup bowls, add a little Greek yogurt (1/2 TBspoon, more if you like), and complete with stripes of pancetta or prosciutto, previously toasted in a non-stick skillet (without adding fat or oil).