2 tbsp. butter
1 medium onion, chopped
1 lb. kohlrabi bulbs, peeled and chopped
2 1/2 C vegetable stock
2 1/2 C milk
1 bay leaf
Salt and black pepper
Kohlrabi leaves chiffonade (optional) for garnish
Melt butter in a large pan with a lid. Add onions and cook gently until soft, about 10 minutes. Add kohlrabi and cook 2 minutes. Add vegetable stock, milk and bay leaf to pan, and bring to a boil. Cover, reduce heat to low and simmer 25 minutes or until kohlrabi is tender. Let cool a few minutes and remove bay leaf.
Using an immersion blender, conventional blender or food processor, puree soup until smooth. You may want to strain the soup through a fine sieve if the kohlrabi is especially fibrous. Season to taste with salt and pepper. Serve in heated bowls garnish with chiffonade of kohlrabi leaves (see below), and with a hearty bread of your choice.
To chiffonade the kohlrabi leaves, blanch them briefly first, then strip them from their stem, roll into a tight log and slice very thinly crosswise.