You can use all broth in this soup from Hungary. Feel free to add other roots, herbs, etc., though I really like the simplicity of this soup. It’s light and would be perfect for a first course, or as part of a meal with sandwiches.
2 T butter or oil
1 medium onion, chopped
3 c peeled and chopped kohlrabi
2 1/2 c broth
2 1/2 c milk, or milk substitute
1 bay leaf
salt and black pepper, to taste
1. Melt butter or heal oil in a soup pot. Add onions and cook gently until soft, about 8 minutes. Add kohlrabi and cook, stirring, for 2 minutes.
2. Add broth, milk if using, and bay leaf. Bring just to the boil. Cover, reduce heat to low and simmer for 25 minutes or until kohlrabi is tender. Let cool a few minutes and remove bay leaf.
3. Using an immersion blender, conventional blender or food processor, purée soup until smooth. You could strain the soup through a fine sieve if you like (kohlrabi can be fibrous). Return to pot to heat through if necessary, season to taste with salt and pepper and serve.