Bring vegetable stock and 2 cups of water to a boil in a large pot.

Add peeled and diced potatoes and finely chopped leek to the boiling stock.

Return to a boil, then reduce heat and simmer for 10-15 minutes, or until the potatoes are very tender.

In a separate bowl, mix 6 tablespoons of the hot soup liquid with cream cheese and horseradish sauce until smooth and well combined.

Using a potato masher, mash the soup in the pot until it reaches a chunky consistency.

Stir in half of the cream cheese mixture into the mashed soup and combine thoroughly.

Divide the soup evenly between 4 serving bowls.

Swirl the remaining cream cheese mixture into each bowl of soup.

Arrange slices or pieces of smoked salmon in each bowl on top of the soup.

Sprinkle chopped chives and freshly ground black pepper over each serving before serving.