Unpack the beef fillet and pat dry, then seal in a vacuum bag with the rosemary and peeled garlic. Place the bag in the Sous-vide bath at 53 - 54 ° C. The meat stays here for 2 hours.
Clean the mushrooms and spring onions and cut into pieces. When the meat comes out of the bath, you can start preparing the side dish so that it still has bite and is not completely overcooked.
Take the meat out of the bag and grill on the grill using the flip-flip method, turning every 20-30 seconds until a nice crust has formed.
Fry the mushrooms and spring onions in a hot pan for about 5 - 10 minutes and only season with a little salt and pepper.