Step 1

Cook onion and garlic slowly in the butter for 2 - 3 minutes until tender but not browned.

Step 2

Add the cucumber and celery root chunks, and carrot. Stir and sauté for 1 – 2 minutes.

Step 3

Add water and crumbled vegetable cube. Bring to a boil, then lower the flame, and simmer, partially covered, for 15 minutes.

Step 4

Remove the soup from the heat, and purée the soup with a stick blender (or in batches in a regular blender) until silky smooth.

Step 5

Just before serving, beat in sour cream. Season with white pepper.