Step 1

Warm the olive oil in a large pot over medium heat and sauté the onion, garlic and half of the celery until the onion is soft and translucent. Meanwhile, peel and chop 3 of the potatoes (makes roughly 2 cups). Add the potatoes, white wine and 3 cups of the stock to the pot and bring to a boil.

Step 2

Lower heat and simmer for 7-10 minutes, or until potatoes are very soft. Remove pot from heat. Blend until smooth with an immersion blender or in batches with a countertop blender. If needed, add some of the remaining 1 cup stock to thin soup to desired consistency. Taste and add a little salt if needed.

Step 3

Return pot to stove and bring back to a simmer. Meanwhile, dice the carrot and remaining potato. Add the diced carrot, potato and remaining chopped celery to the soup and simmer for 10 minutes, or until the potato pieces are soft but not falling apart. Add the fish and simmer for 5 minutes more, or until fish is cooked through. Taste and add a little vinegar if soup needs some brightness. Garnish each serving with celery leaves or parsley.