Clean the green peas and put it into hot water for 5 minutes. Grate of slice carrot and sauté on butter; after a while, mince onion and sauté both on butter until onion is translucent.
Add finely sliced pancetta and sauté not more than 5 minutes. Add flour and fry about 2 minutes, than add cold water and make creamy liquid (like sauce veloute).
Cut green parts of spring onion, mince parsley and celery leaves and add into pot. Add green pea and about 1 liter of beef stock. Add salt and pepper.
Cook until green peas are soft. When soft, remove green pea and blend it into puree (leave 1/6 of peas untouched). You can blend it with stick blender so you do not have to remove geen pea. Add thyme and cook 15 minutes.
At the end add sour cream and minced chive. Serve with croutons.