Clean the beef, season with salt and pepper and sear well on both sides in a little oil, whole, in a pressure cooker.
In the meantime, wash, trim and chop the onion, celery and carrots. Add the vegetables to the beef, fry briefly, add water and cook in the pressure cooker for 15 minutes.
Open the pressure cooker under cold water and mix the crème fraîche with flour for the sauce (prepare a Gmachtl).
Take out the meat, put some vegetables on the side, puree the rest. Thicken with the Gmachtl.
Return the meat and vegetables to the pot, bring to the boil again briefly and then arrange as desired.