Step 1

Heat the oil in a large saucepan over medium heat. Add the onion, garlic and thyme and cook, stirring, for 1 minute or until the onion softens slightly.

Step 2

Increase heat to high. Add the stock and potato, and bring to the boil. Cook, stirring occasionally, for 10 minutes or until the potato is tender.

Step 3

Add the zucchini and cook for 2 minutes or until the zucchini is soft. Remove from heat. Stir in the parsley, parmesan and sour cream.

Step 4

Pour half the zucchini mixture into the bowl of a food processor and process until smooth. Transfer to a clean saucepan. Repeat with remaining zucchini mixture. Ladle among serving bowls. Season with pepper and serve with extra parmesan and crusty bread.