Finely mince the onion.

Saute the minced onion on butter until translucent.

Cut and mince all vegetables into small pieces.

Add the minced vegetables to the sauteed onion.

Add beef stock to the pot.

Season with salt and pepper.

Cook for 40 minutes, or until the vegetables are soft.

Blend the soup with an immersion blender until creamy.

Add thyme and nutmeg.

Cook for an additional 10-15 minutes.

Stir in sour cream before serving.

Serve hot with croutons.