LOOKING THROUGH THE fridge the other day I found, among other things, an old parsnip, two onion halves, a peeled Yukon Gold potato, and a partial head of celery that was going limp. There was also a nearly full quart of chicken stock that needed to be used immediately.

To these ingredients I added the beautifully robust wild watercress picked in California and some black trumpet mushrooms from the same trip.

2 – 3 tbsp butter
1 onion, chopped
2 cloves garlic, chopped
3 stalks celery, chopped
1 medium parsnip, chopped
1 potato, chopped
3 cups vegetable or chicken stock
1 large bunch watercress, stemmed
salt and white pepper, to taste

1. In a soup pot, saute onions in butter over medium heat until slightly caramelized. Add garlic and celery and cook another few minutes until tender, then add chopped parsnip and potato and cook several more minutes.

2. Stir in stock and simmer for 15 or more minutes until parsnip and potato are tender.

3. Add the watercress, allowing it to wilt. Use an immersion blender to puree the soup. Adjust seasonings.

As a finishing touch, I made a crouton with toasted and garlic-rubbed rosemary bread covered in melted mozzarella cheese and topped with a trio of sautéed black trumpets.